Science.gov

Sample records for african plate relative

  1. Relative Motion of Africa Plate with Respect to South African Kalahari Craton

    NASA Astrophysics Data System (ADS)

    Njoroge, Mary; Malservisi, Rocco; Hugentobler, Urs; Voytenko, Denis

    2014-05-01

    The presence of the Rift Valley within the African continent and its eventual propagation southward in the Okavango rift zone (ORZ) strongly affects the regional seismic hazard evaluation. Here we use a comparison of the motion inferred from the South African GPS network TrigNet with the motion of instruments with the rest of the African continent to evaluate the propagation of the Rift Valley to Botswana. We use data from all the available GPS stations located in the Nubian plate to develop two reference frames north and south of the ORZ. The data was processed using two major codes (Bernese and Gipsy-oasis) to evaluate effects on the references due to processing assumptions. Given the importance of uncertainties in understanding the significance of small signals, a full analysis of the Allan Variance of the velocity has been performed. Preliminary results suggest that although still within the limits of the uncertainties, the data are compatible with relative motion between the TrigNet network and the rest of Nubia, and does not exclude a possible counter clockwise rotation of the South African Kalahari craton with respect to the Nubian plate, and thus a southward propagation of the Rift Valley.

  2. African absolute plate motion and True Polar Wander at about 50Ma

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Wessel, P.

    2011-12-01

    Using new data set of seamount ages on the African plate, a model of motion of the African plate relative to the African hotspots are calculated by the Polygonal Finite Rotation Method; PFRM (Harada and Hamano, 2000). The new motion of the African plate has more abrupt change at about 50Ma than the previous models of the African plate mainly due to the PFRM which can allow the finite pole of the plate rotation to move continuously. The new model of the motion fits positions and ages of the almost all seamounts which are created by the African hotspots, whereas the previous models do not fit with positions of northwestern hotspots of the African plate such as Canary, Cape Verde, Meteor and Bathymetric hotspot. The new model suggests that the African plate rotated counter clockwise abruptly at about 50Ma. To compare the 50Ma abrupt change with coeval event at the Pacific plate motion, we utilized the paleomagnetic data from both plates. From the apparent geomagnetic polar wander path of the African plate and African plate motion relative to the African hotspots, we calculated geomagnetic polar motion relative to the African hotspots. Similarly, we calculated geomagnetic polar motion relative to the Pacific hotspots from the Pacific sets of paleomagnetic data and plate motion. The geomagnetic polar motion or true polar wander should be only one, therefore we can calculate relative motion of the African hotspots and the Pacific hotspots. The result shows that there was no significant motion between two groups of hotspots since about 70Ma. The new true polar wander path since 70Ma, thus, presented by averaging the two models of motions, and this has about 90 degree clockwise change of directions at about 50Ma. This study strongly suggests below. 1, There was coeval event of the African plate motion with Hawaii-Emperor bend event at the Pacific plate. 2, There was no significant relative motion between global hotspots for the time scale of 70Myr even though there was

  3. Plio-Quaternary paleostresses in the Atlantic passive margin of the Moroccan Meseta: Influence of the Central Rif escape tectonics related to Eurasian-African plate convergence

    NASA Astrophysics Data System (ADS)

    Chabli, Ahmed; Chalouan, Ahmed; Akil, Mostapha; Galindo-Zaldívar, Jesús; Ruano, Patricia; Sanz de Galdeano, Carlos; López-Garrido, Angel Carlos; Marín-Lechado, Carlos; Pedrera, Antonio

    2014-07-01

    The Atlantic Moroccan Meseta margin is affected by far field recent tectonic stresses. The basement belongs to the variscan orogen and was deformed by hercynian folding and metamorphism followed by a post-Permian erosional stage, producing the flat paleorelief of the region. Tabular Mesozoic and Mio-Plio-Quaternary deposits locally cover the Meseta, which has undergone recent uplift, while north of Rabat the subsidence continues in the Gharb basin, constituting the foreland basin of the Rif Cordillera. The Plio-Quaternary sedimentary cover of the Moroccan Meseta, mainly formed by aeolian and marine terraces deposits, is affected by brittle deformations (joints and small-scale faults) that evidence that this region - considered up to date as stable - is affected by the far field stresses. Striated faults are recognized in the oldest Plio-Quaternary deposits and show strike-slip and normal kinematics, while joints affect up to the most recent sediments. Paleostress may be sorted into extensional, only affecting Rabat sector, and three main compressive groups deforming whole the region: (1) ENE-WSW to ESE-WNW compression; (2) NNW-SSE to NE-SW compression and (3) NNE-SSW compression. These stresses can be attributed mainly to the NW-SE oriented Eurasian-African plate convergence in the western Mediterranean and the escape toward the SW of the Rif Cordillera. Local paleostress deviations may be related to basement fault reactivation. These new results reveal the tectonic instability during Plio-Quaternary of the Moroccan Meseta margin in contrast to the standard passive margins, generally considered stable.

  4. Current plate velocities relative to the hotspots incorporating the NUVEL-1 global plate motion model

    SciTech Connect

    Gripp, A.E.; Gordon, R.G. )

    1990-07-01

    NUVEL-1 is a new global model of current relative plate velocities which differ significantly from those of prior models. Here the authors incorporate NUVEL-1 into HS2-NUVEL1, a new global model of plate velocities relative to the hotspots. HS2-NUVEL1 was determined from the hotspot data and errors used by Minster and Jordan (1978) to determine AM1-2, which is their model of plate velocities relative to the hotspots. AM1-2 is consistent with Minster and Jordan's relative plate velocity model RM2. Here the authors compare HS2-NUVEL1 with AM1-2 and examine how their differences relate to differences between NUVEL-1 and RM2. HS2-NUVEL1 plate velocities relative to the hotspots are mainly similar to those of AM1-2. Minor differences between the two models include the following: (1) in HS2-NUVEL1 the speed of the partly continental, apparently non-subducting Indian plate is greater than that of the purely oceanic, subducting Nazca plate; (2) in places the direction of motion of the African, Antarctic, Arabian, Australian, Caribbean, Cocos, Eurasian, North American, and South American plates differs between models by more than 10{degree}; (3) in places the speed of the Australian, Caribbean, Cocos, Indian, and Nazca plates differs between models by more than 8 mm/yr. Although 27 of the 30 RM2 Euler vectors differ with 95% confidence from those of NUVEL-1, only the AM1-2 Arabia-hotspot and India-hotspot Euler vectors differ with 95% confidence from those of HS2-NUVEL1. Thus, substituting NUVEL-1 for RM2 in the inversion for plate velocities relative to the hotspots changes few Euler vectors significantly, presumably because the uncertainty in the velocity of a plate relative to the hotspots is much greater than the uncertainty in its velocity relative to other plates.

  5. Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames.

    NASA Astrophysics Data System (ADS)

    Azzouzi, R.

    2009-04-01

    Determination of recent horizontal crustal movements and deformations of African and Eurasian plates in western Mediterranean region using geodetic-GPS computations extended to 2006 (from 1997) related to NAFREF and AFREF frames. By: R. Azzouzi*, M. Ettarid*, El H. Semlali*, et A. Rimi+ * Filière de Formation en Topographie Institut Agronomique et Vétérinaire Hassan II B.P. 6202 Rabat-Instituts MAROC + Département de la Physique du Globe Université Mohammed V Rabat MAROC This study focus on the use of the geodetic spatial technique GPS for geodynamic purposes generally in the Western Mediterranean area and particularly in Morocco. It aims to exploit this technique first to determine the geodetic coordinates on some western Mediterranean sites. And also this technique is used to detect and to determine movements cross the boundary line between the two African and Eurasian crustal plates on some well chosen GPS-Geodynamics sites. It will allow us also to estimate crustal dynamic parameters of tension that results. These parameters are linked to deformations of terrestrial crust in the region. They are also associated with tectonic constraints of the study area. The usefulness of repeated measurements of these elements, the estimate of displacements and the determination of their temporal rates is indisputable. Indeed, sismo-tectonique studies allow a good knowledge of the of earthquake processes, their frequency their amplitude and even of their prediction in the world in general and in Moroccan area especially. They allow also contributing to guarantee more security for all most important management projects, as projects of building great works (dams, bridges, nuclear centrals). And also as preliminary study, for the most important joint-project between Europe and Africa through the Strait of Gibraltar. For our application, 23 GPS monitoring stations under the ITRF2000 reference frame are chosen in Eurasian and African plates. The sites are located around the

  6. Convection pattern and stress system under the African plate

    NASA Technical Reports Server (NTRS)

    Liu, H.-S.

    1977-01-01

    Studies on tectonic forces from satellite-derived gravity data have revealed a subcrustal stress system which provides a unifying mechanism for uplift, depression, rifting, plate motion and ore formation in Africa. The subcrustal stresses are due to mantle convection. Seismicity, volcanicity and kimberlite magmatism in Africa and the development of the African tectonic and magnetic features are explained in terms of this single stress system. The tensional stress fields in the crust exerted by the upwelling mantle flows are shown to be regions of structural kinship characterized by major concentration of mineral deposits. It is probable that the space techniques are capable of detecting and determining the tectonic forces in the crust of Africa.

  7. Cycloid kinematics of relative plate motion

    SciTech Connect

    Cronin, V.S.

    1987-11-01

    The trajectory of a point on one plate as observed from another plate is generally a complex curve and not a small circle around a single axis of relative motion, as is commonly assumed. The shape of the relative-motion path is given the general name spherical cycloid because of its morphological similarity to cycloid planetary trajectories described by early astronomers. The cycloid relative-motion model predicts that the following phenomena occur during finite displacements: (1) the relative velocity and the curvature of the trajectory of a point on one plate relative to another plate varies systematically; (2) plates wobble relative to one another; and (3) the angle of convergence and/or divergence varies systematically along the length of any given transform fault. The small-circle relative-motion model, whereby transform faults have been considered lines of pure slip along which crust is conserved, is not generally valid for finite relative displacements.

  8. Computing relative plate velocities: a primer

    SciTech Connect

    Bevis, M.

    1987-08-01

    Standard models of present-day plate motions are framed in terms of rates and poles of rotation, in accordance with the well-known theorem due to Euler. This article shows how computation of relative plate velocities from such models can be viewed as a simple problem in spherical trigonometry. A FORTRAN subroutine is provided to perform the necessary computations.

  9. African American Preschoolers' Language, Emergent Literacy Skills, and Use of African American English: A Complex Relation

    ERIC Educational Resources Information Center

    Connor, Carol McDonald; Craig, Holly K.

    2006-01-01

    Purpose: This study examined the relation between African American preschoolers' use of African American English (AAE) and their language and emergent literacy skills in an effort to better understand the perplexing and persistent difficulties many African American children experience learning to read proficiently. Method: African American…

  10. Toward Understanding Korean and African American Relations.

    ERIC Educational Resources Information Center

    Chang, Edward Taehan

    1996-01-01

    Presents a lesson plan that examines the economic, cultural, and ideological factors that influence Korean and African American relations. Discusses how the two groups perceive each other and situates the role of race and class in this relationship. Includes informational handouts and discussion questions. (MJP)

  11. Caribbean tectonics and relative plate motions

    NASA Technical Reports Server (NTRS)

    Burke, K.; Dewey, J. F.; Cooper, C.; Mann, P.; Pindell, J. L.

    1984-01-01

    During the last century, three different ways of interpreting the tectonic evolution of the Gulf of Mexico and the Caribbean have been proposed, taking into account the Bailey Willis School of a permanent pre-Jurassic deep sea basin, the Edward Suess School of a subsided continental terrain, and the Alfred Wegener School of continental separation. The present investigation is concerned with an outline of an interpretation which follows that of Pindell and Dewey (1982). An attempt is made to point out ways in which the advanced hypotheses can be tested. The fit of Africa, North America, and South America is considered along with aspects of relative motion between North and South America since the early Jurasic. Attention is given to a framework for reconstructing Caribbean plate evolution, the evolution of the Caribbean, the plate boundary zones of the northern and southern Caribbean, and the active deformation of the Caribbean plate.

  12. The satellite magnetic anomaly of Ahaggar - Evidence for African Plate motion

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.; Brown, C. R.

    1985-01-01

    The Ahaggar volcanic province of North Central Africa is considered a region of excess heat flow (hot spot) and hence elevated Curie isotherm. Using a modified version of the Parker FFT potential field representation, magnetic signals were calculated at Magsat altitudes for models in which the African Plate is both fixed and moving. The moving-plate model extends the Curie isotherm anomaly in the direction of plate motion and provides a satisfactory match to vertical component anomaly data when the magnitude of plate velocity is 0.75 cm/yr. Although the signal levels are marginal for the scalar component anomalies of this region, the same model provides an adequate match to this data set and is clearly preferable to a fixed-plate model.

  13. Estimating the stresses within the lithosphere: parameter check with applications to the African Plate

    NASA Astrophysics Data System (ADS)

    Medvedev, Sergei; Werner, Stephanie; Steinberger, Bernhard; "African Plate" Working Group

    2010-05-01

    Several mechanisms control the state of stress within plates on Earth. The list is rather long, but well-known and includes ridge push, mantle drag, stresses invoked by lateral variations of lithospheric density structure and subduction processes. We attempt to quantify the influence of these mechanisms and to construct a reliable model to understand modern and palaeo-stresses using the African plate (TAP) as an example. Previous studies explained stress patterns and their evolution solely by assigning different rheological properties to sub-domains and their boundaries. Such an approach often leads to unrealistically high variations of properties within a modeled plate. In our approach we find the best possible agreement with observations before differentiating between sub-domains of TAP. The finite-element based suite ProShell was utilized to calculate stresses on the real geometry of TAP (non-planar). The approach allows us to combine several data sets and to estimate stresses caused by lateral and vertical distribution of properties within the lithosphere, to quantify the in-plane and bending stresses, to account for forces due to ridge push and mantle heterogeneities and mantle flow. The modeled results are tested and iterated to match the observed stress pattern and potential fields as good as possible. The starting model is based on the CRUST2 data set to construct the model crust and half-space cooling model to approximate properties of the lithospheric mantle. The results however, are not satisfactory, and might be related to oversimplifications in the uniform model of lithosphere or/and to the unrealistic representation of the CRUST2 model in certain areas of TAP. The latter was also shown by simple evaluation using gravity forward modeling of the model boundaries. The model implementation of the crustal structure calculated from simple gravity inversion or derived through isostatical considerations agree better to today's observed stress pattern.

  14. Plate Kinematic model of the NW Indian Ocean and derived regional stress history of the East African Margin

    NASA Astrophysics Data System (ADS)

    Tuck-Martin, Amy; Adam, Jürgen; Eagles, Graeme

    2015-04-01

    Starting with the break up of Gondwana, the northwest Indian Ocean and its continental margins in Madagascar, East Africa and western India formed by divergence of the African and Indian plates and were shaped by a complicated sequence of plate boundary relocations, ridge propagation events, and the independent movement of the Seychelles microplate. As a result, attempts to reconcile the different plate-tectonic components and processes into a coherent kinematic model have so far been unsatisfactory. A new high-resolution plate kinematic model has been produced in an attempt to solve these problems, using seafloor spreading data and rotation parameters generated by a mixture of visual fitting of magnetic isochron data and iterative joint inversion of magnetic isochron and fracture zone data. Using plate motion vectors and plate boundary geometries derived from this model, the first-order regional stress pattern was modelled for distinct phases of margin formation. The stress pattern is correlated with the tectono-stratigraphic history of related sedimentary basins. The plate kinematic model identifies three phases of spreading, from the Jurassic to the Paleogene, which resulted in the formation of three main oceanic basins. Prior to these phases, intracontinental 'Karoo' rifting episodes in the late Carboniferous to late Triassic had failed to break up Gondwana, but initiated the formation of sedimentary basins along the East African and West Madagascan margins. At the start of the first phase of spreading (183 to 133 Ma) predominantly NW - SE extension caused continental rifting that separated Madagascar/India/Antarctica from Africa. Maximum horizontal stresses trended perpendicular to the local plate-kinematic vector, and parallel to the rift axes. During and after continental break-up and subsequent spreading, the regional stress regime changed drastically. The extensional stress regime became restricted to the active spreading ridges that in turn adopted trends

  15. African plate motions constraining and Euler pole determination using permanent GPS data

    NASA Astrophysics Data System (ADS)

    Deprez, A.; Masson, F.; Doubre, C.; Ulrich, P.

    2012-04-01

    IPGS-EOST, CNRS-Université de Strasbourg, 5 rue Descartes, 67084 Strasbourg Cedex France. GPS data of permanent stations in Africa allowed us to calculate the position time series and the absolute velocity of many points on this continent during a twelve-year period (1999-2011). The data processing was made thanks to the GAMIT/GLOBK software. The results lead us to select reliable sites presenting a quantity of data large enough to limit the uncertainty. We took care too that this sites did not undergo local deformation and, in particular, that they were far from the plate boundaries. Then we adopted a technique based on William's method to remove the data jumps and the seasonal variations from the position time series. Station sets was brought together function of their position and of plate and micro-plate boundaries from precedents studies. The main conclusions of this velocity field study were as follows: (1) We achieve, with coherent data samples, to find pole coordinates for plates and micro-plates defined by Stamps et al. (2007). These coordinates differ slightly from values found in precedent studies (Altamimi et al., 2012 (in review); Stamps et al., 2007), which were taken as a priori values. (2) Many African stations were too recent to give reliable velocity and the pole coordinate accuracy could be improved in the next few years. (3) The presence of large zones of local deformation particularly on both sides of the East African Rift prevents from the use of many data for the pole determination.

  16. Seismotectonic features of the African plate: the possible dislocation of a continent

    NASA Astrophysics Data System (ADS)

    Meghraoui, Mustapha

    2014-05-01

    , the Libyan rifting and Maghreb thrusting. Although bearing a relatively slow deformation with regards to the East Africa Rift System, the Nubia plate previously considered as a homogeneous tectonic block appears to be dislocating progressively also forming a system of microplates. A synthesis of earthquake studies and regional deformation exposed in a seismotectonic map hitherto serves as a basis for the seismic hazard evaluations and the reduction of seismic risks. * IGCP/SIDA: International Geoscience Program/Swedish International Cooperation Authority http://www.unesco.org/science/IGCP IGCP-601 Working Group: Paulina Amponsah (Ghana Atomic Energy Commission), Atalay Ayele (Addis Ababa University, Ethiopia), Bekoa Ateba (Inst. of Geol. and Min. Res., Buea, Cameroon), Abdelhakim Ayadi (CRAAG, Algeria), Abdunnur Bensuleman (University of Tripoli, Libya), Damien Delvaux (Royal Museum for Central Africa, Tervuren, Belgium), Mohamed El Gabry (National Research Institute of Geophysics, Cairo, Egypt), Rui-Manuel Fernandes (Universidade da Beira Interior, Portugal), Mustapha Meghraoui (IPG Strasbourg, France), Vunganai Midzi & Magda Roos (Council for Geoscience, Pretoria, South Africa), and Youssef Timoulali (CNRST, Rabat, Morocco).

  17. Inherited segmentation of the Iberian-African margins and tectonic reconstruction of a diffuse plate boundary.

    NASA Astrophysics Data System (ADS)

    Fernàndez, Manel; Torne, Montserrat; Vergés, Jaume; Casciello, Emilio

    2016-04-01

    Diffuse plate-boundary regions are characterized by non-well defined contacts between tectonic plates thus making difficult their reconstruction through time. The Western Mediterranean is one of these regions, where the convergence between the African and Iberian plates since Late Cretaceous resulted in the Betic-Rif arcuate orogen, the Gulf of Cadiz imbricate wedge, and the Alboran back-arc basin. Whereas the Iberia-Africa plate boundary is well defined west to the Gorringe Bank and along the Gloria Fault, it becomes much more diffuse eastwards with seismicity spreading over both the south-Iberian and north-African margins. Gravity data, when filtered for short wavelengths, show conspicuous positive Bouguer anomalies associated with the Gorringe Bank, the Gulf of Cadiz High and the Ronda/Beni-Bousera peridotitic massifs reflecting an inherited Jurassic margin segmentation. The subsequent Alpine convergence between Africa and Iberia reactivated these domains, producing crustal-scale thrusting in the Atlantic segments and eventually subduction in the proto-Mediterranean segments. The Jurassic segmentation of the Iberia-Africa margins substantiates the double-polarity subduction model proposed for the region characterized by a change from SE-dipping polarity in the Gorringe, Gulf of Cadiz and Betic-Rif domains, to NW-dipping polarity in the proto-Algerian domain. Therefore, the Algerian and Tyrrhenian basins in the east and the Alboran basin in the west are the result of SSE-E and NW-W retreating slabs of oceanic and/or hyper-extended Tethyan domains, respectively.

  18. Indian and African plate motions driven by the push force of the Réunion plume head.

    PubMed

    Cande, Steven C; Stegman, Dave R

    2011-07-06

    Mantle plumes are thought to play an important part in the Earth's tectonics, yet it has been difficult to isolate the effect that plumes have on plate motions. Here we analyse the plate motions involved in two apparently disparate events--the unusually rapid motion of India between 67 and 52 million years ago and a contemporaneous, transitory slowing of Africa's motion--and show that the events are coupled, with the common element being the position of the Indian and African plates relative to the location of the Réunion plume head. The synchroneity of these events suggests that they were both driven by the force of the Réunion plume head. The recognition of this plume force has substantial tectonic implications: the speed-up and slowdown of India, the possible cessation of convergence between Africa and Eurasia in the Palaeocene epoch and the enigmatic bends of the fracture zones on the Southwest Indian Ridge can all be attributed to the Réunion plume.

  19. The Syntax of Zero in African American Relative Clauses

    ERIC Educational Resources Information Center

    Sistrunk, Walter

    2012-01-01

    African American relative clauses are distinct from Standard English relative clauses in allowing zero subject relatives and zero appositive relatives. Pesetsky and Torrego's (2003) (P&T) analysis of the subject-nonsubject asymmetry in relative clauses accounts for zero object relatives while restricting zero subject relatives. P&T…

  20. A test of alternative Caribbean plate relative motion models

    NASA Technical Reports Server (NTRS)

    Stein, Seth; Demets, Charles; Gordon, Richard G.; Brodholt, John; Argus, Don

    1988-01-01

    The new NUVEL-1 data set for global relative plate motions is used here to discriminate between the two prevailing models for Caribbean plate motion. One model, by Jordan (1975), assumes that North America-Caribbean motion is reflected by the spreading rate inferred from magnetic anomalies at the Cayman Spreading Center and the azimuths of nearby transforms. The other model, by Sykes et al. (1982), uses rates and azimuths inferred from the geometry of the Lesser Antilles Wadati-Benioff zone. Overall, it is found that the data fit the Jordan geometry better, that the data used in global plate motion models are more suitable than rates and azimuths inferred from the geometry of the Wadati-Benioff zone for determining relative motions, and that incorporation of all relevant plate boundaries is essential.

  1. A wide-angle seismic survey of the Hecataeus Ridge, south of Cyprus: a microcontinental block from the African plate docked in a subduction zone?

    NASA Astrophysics Data System (ADS)

    Rahimi, Ayda; Welford, Kim; Hall, Jeremy; Hübscher, Christian; Louden, Keith; Ehrhardt, Axel

    2013-04-01

    Cyprus lies at the southern edge of the Aegean-Anatolian microplate, caught in the convergence of Africa and Eurasia. Subduction of the African plate below Cyprus has probably ceased and this has been attributed to the docking in the subduction zone of the Eratosthenes Seamount microcontinental fragment on the northern edge of the African plate. In early 2010, on R.V. Maria S. Merian, we conducted a wide-angle seismic survey to test the hypothesis that the Hecataeus Ridge, another possible microcontinental block lying immediately offshore SE Cyprus, might be related to an earlier docking event. The upper crust of southern Cyprus is dominated by ophiolites, with seismic velocities of up to 7 km s-1. A wide angle seismic profile along Hecataeus Ridge was populated with 15 Canadian and German ocean-bottom seismographs at 5 km intervals and these recorded shots from a 6000 cu. in. air gun array, fired approximately every 100 m. Rough topography of the seabed has made picking of phases and their modelling a demanding task. Bandpass and coherency filtering have enabled us to pick phases out to around 80 km. Tomographic inversion of short-range first arrivals provided an initial model of the shallow sub-seabed structure. Forward modelling by ray-tracing, using the code of Zelt and Smith, was then used to model crustal structure down to depths of around 20 km, with occasional evidence of reflections from deeper boundaries (Moho?). Modelling results provide good control on P-wave velocities in the top 20 km and some indications of deeper events. There is no evidence of true velocities approaching 7 km/s in the top 20 km below the Ridge that might indicate the presence of ophiolitic rocks. Regional gravity and magnetic field data tend to support this proposition. We thus conclude that Hecataeus Ridge is not composed of characteristically ophiolitic, Cyprus (upper plate) crust, and it might well be derived from the African (lower) plate.

  2. Stress-related disorders in African-American children.

    PubMed Central

    Bell, C. C.

    1997-01-01

    Children exposed to traumatic stress are vulnerable to a variety of stress-related disorders other than classical post-traumatic stress disorder. Several case histories are presented to illustrate some of the diversity of how traumatic stress may manifest in children. African-American children are the main focus of this article as political, economic, social, and morbidity and mortality indicators suggest that African-American children are at high risk for exposure to potentially traumatic stressors. Different presentations of traumatic, stress are discussed in an effort to broaden our understanding of the outcome of traumatic stress to fully help traumatized children. PMID:9170834

  3. The San Andreas fault experiment. [gross tectonic plates relative velocity

    NASA Technical Reports Server (NTRS)

    Smith, D. E.; Vonbun, F. O.

    1973-01-01

    A plan was developed during 1971 to determine gross tectonic plate motions along the San Andreas Fault System in California. Knowledge of the gross motion along the total fault system is an essential component in the construction of realistic deformation models of fault regions. Such mathematical models will be used in the future for studies which will eventually lead to prediction of major earthquakes. The main purpose of the experiment described is the determination of the relative velocity of the North American and the Pacific Plates. This motion being so extremely small, cannot be measured directly but can be deduced from distance measurements between points on opposite sites of the plate boundary taken over a number of years.

  4. Understanding lithospheric stresses: systematic analysis of controlling mechanisms with applications to the African Plate

    NASA Astrophysics Data System (ADS)

    Medvedev, Sergei

    2016-10-01

    Many mechanisms control the state of stress within Earth plates. First-order well-known mechanisms include stresses induced by lateral variations of lithospheric density structure, sublithospheric tractions, ridge push and subduction pull. In this study, we attempt to quantify the influence of these mechanisms to understand the origin of stresses in the lithosphere, choosing the African plate (TAP) as an example. A finite-element based suite, Proshell, was developed to combine several data sets, to estimate the gravitational potential energy (GPE) of the lithosphere and to calculate stresses acting on the real (non-planar) geometry of TAP. We introduce several quantitative parameters to measure the degree of fit between the model and observations. Our modelling strategy involves nine series of numerical experiments. We start with the simplest possible model and then, step by step, build it up to be a more physically realistic model, all the while discussing the influence of each additional component. The starting (oversimplified) model series (1) is based on the CRUST2 data set for the crust and a half-space-cooling approximation of the lithospheric mantle. We then describe models (series 2-5) that account for lithospheric mantle density heterogeneities to build a more reliable GPE model. The consecutive series involve basal traction from the convective mantle (series A, C) and the rheological heterogeneity of the TAP via variations in its effective elastic thickness (series B, C). The model quality reflects the increase in complexity between series with an improving match to observed stress regimes and directions. The most complex model (series D) also accounts for the bending stresses in the elastic lithosphere and achieves a remarkably good fit to observations. All of our experiments were based on the iteration of controlling parameters in order to achieve the best fit between modelled and observed stresses, always considering physically feasible values. This

  5. Gender as a Moderator of the Relation between Race-Related Stress and Mental Health Symptoms for African Americans

    ERIC Educational Resources Information Center

    Greer, Tawanda M.; Laseter, Adrian; Asiamah, David

    2009-01-01

    The present study tested gender as a moderator of the relationship between race-related stress and mental health symptoms among African American adults. Because African American women are exposed to stressors associated with race and gender, we hypothesized that African American women would have higher levels of race-related stress and more severe…

  6. The Rift Valley of African Plate in Elasto-Plastic Creeping over Magma Motion

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigehisa

    2016-04-01

    This is a brief note to a problem on the Rift Valley in the eastern Africa. It is said that this valley was formed in an age 20,000,000 years before present though the valley is yet continuing to move eastward at an annual rate of about 5 cm/year in a geographical trend. Adding to some of the scientists tell that the separation threat of the easternAfrica from the mother land of the Africa under the effect of African crust motion over the magma. However, it is now geological understanding that the land of the Africa has been kept its basic coastal configulation in geographic pattern since the time more than 20,000,000 years before present. Sothat, it is hard to consider the above noted African land separation by part could be in the next age in a time scale of 20,000,000 years. As far as, we concern the geographic data obtaoned by the ground based survey of the African typical mountain peaks, the highest mountain peak 5885m (in 1980) is for Kilimanjaro, Kibo Peak though one of the scientific almanacs tells us its peak height as 5890m (in 2009). As for the Mount Kenia, the peak height is as 5199m (in 1980) and 5200m(in 2009). At a glance, it looks to be a trend in altimetry of the African typical mountain. Now, what trends are noted for the peak heights could be taken to suggesting the geological activity on the earth surface to maintain in a spherical shape approximately on the orbit around the Sun. In these several ten years, the digitizing of the data has been promoted even for the topographic patterns on the earth though its time scaling is extremely short comparing to the geological time scaling. Now, it should be found what is effective to monitor any trends of the African crust in motion as well as variations of the mountain peaks.

  7. UHPLC/HRMS Analysis of African Mango (Irvingia gabonensis) Seeds, Extract and Related Dietary Supplements

    PubMed Central

    Sun, Jianghao; Chen, Pei

    2012-01-01

    Dietary Supplements based on an extract from Irvingia gabonensis (African Mango, AM for abbreviation) seeds are one of the popular herbal weight loss dietary supplements in the US market. The extract is believed to be a natural and healthy way to lose weight and improve overall health. However, the chemical composition of African mango based-dietary supplements (AMDS) has never been reported. In this study, the chemical constituents of African mango seeds, African mango seeds extract (AMSE), and different kinds of commercially available African mango based dietary supplements (AMDS) have been investigated using an ultra high-performance liquid chromatography with high resolution mass spectrometry (UHPLC-HRMS) method. Ellagic acid, mono, di, tri-O methyl-ellagic acids and their glycosides were found as major components in African Mango seeds. These compounds may be used for quality control of African Mango extract and related dietary supplements. PMID:22880691

  8. Work Socialization and Adolescents' Work-Related Values in Single-Mother African American Families

    ERIC Educational Resources Information Center

    Toyokawa, Teru; McLoyd, Vonnie C.

    2013-01-01

    This study examined African American mothers' work socialization messages in relation to adolescents' work-related values. Moderation effects of mother-adolescent relation quality on the linkage between maternal socialization messages and adolescents' outcomes were also examined. Participants were 245 single African American mothers and their…

  9. Race-Related Stress, Quality of Life Indicators, and Life Satisfaction among Elderly African Americans.

    ERIC Educational Resources Information Center

    Utsey, Shawn O.; Payne, Yasser A.; Jackson, Ebonique S.; Jones, Antoine M.

    2002-01-01

    Examines the relationships among race-related stress, quality of life indicators, and life satisfaction among elderly African Americans. Results indicated that elderly African American men and women differed significantly with regard to institutional and collective racism-related stress. In addition, institutional racism-related stress was a…

  10. Human polyomavirus related to African green monkey lymphotropic polyomavirus.

    PubMed

    Sauvage, Virginie; Foulongne, Vincent; Cheval, Justine; Ar Gouilh, Meriadeg; Pariente, Kevin; Dereure, Olivier; Manuguerra, Jean Claude; Richardson, Jennifer; Lecuit, Marc; Burguière, Ana; Caro, Valérie; Eloit, Marc

    2011-08-01

    While studying the virome of the skin surface of a patient with a Merkel cell carcinoma (MCC) by using unbiased, high-throughput sequencing, we identified a human polyomavirus nearly identical to human polyomavirus 9, a virus recently reported in blood and urine of renal transplantion patients and closely related to the African green monkey lymphotropic polyomavirus. Specific PCR analysis further identified this virus in 2/8 patients with MCC but in only 1/111 controls without MCC. This virus was shed for ≥20 months by the MCC index patient and was on the skin of the spouse of the index patient. These results provide information on the viral ecology of human skin and raise new questions regarding the pathology of virus-associated skin disorders.

  11. The African Renaissance and its relation to the geosciences: a South African perspective

    NASA Astrophysics Data System (ADS)

    Mtimkulu, M. N.; Motloung, M.; Graham, I. T.; Eriksson, P. G.; Bumby, A. J.

    2001-08-01

    Implicit in the African Renaissance is the synergy between government, the private sector, the educated minority and the disadvantaged majority. For this concept to work, belief and commitment must arise first from the African individual, whatever his or her potential contribution may be. The geosciences in South Africa provide a currently vibrant example of such cooperation, which has the potential to contribute significantly to the upliftment of the country and its neighbouring states. Based largely on personal interviews with various role players, from the Presidency of South Africa, through ministerial levels, the corporate sector and down to the individual, we present a spectrum of viewpoints and initiatives which are starting to result in practical implementation of the African revival. An end to conflict and xenophobia, the entrenchment of democratic government and corporate expression of the entrepreneurial spirit are essential to provide the framework within which the individual African can become a "Renaissance Man or Woman".

  12. African ancestry protects against Alzheimer's disease-related neuropathology.

    PubMed

    Schlesinger, D; Grinberg, L T; Alba, J G; Naslavsky, M S; Licinio, L; Farfel, J M; Suemoto, C K; de Lucena Ferretti, R E; Leite, R E P; de Andrade, M P; dos Santos, A C F; Brentani, H; Pasqualucci, C A; Nitrini, R; Jacob-Filho, W; Zatz, M

    2013-01-01

    Previous studies in dementia epidemiology have reported higher Alzheimer's disease rates in African-Americans when compared with White Americans. To determine whether genetically determined African ancestry is associated with neuropathological changes commonly associated with dementia, we analyzed a population-based brain bank in the highly admixed city of São Paulo, Brazil. African ancestry was estimated through the use of previously described ancestry-informative markers. Risk of presence of neuritic plaques, neurofibrillary tangles, small vessel disease, brain infarcts and Lewy bodies in subjects with significant African ancestry versus those without was determined. Results were adjusted for multiple environmental risk factors, demographic variables and apolipoprotein E genotype. African ancestry was inversely correlated with neuritic plaques (P=0.03). Subjects with significant African ancestry (n=112, 55.4%) showed lower prevalence of neuritic plaques in the univariate analysis (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.55-0.95, P=0.01) and when adjusted for age, sex, APOE genotype and environmental risk factors (OR 0.43, 95% CI 0.21-0.89, P=0.02). There were no significant differences for the presence of other neuropathological alterations. We show for the first time, using genetically determined ancestry, that African ancestry may be highly protective of Alzheimer's disease neuropathology, functioning through either genetic variants or unknown environmental factors. Epidemiological studies correlating African-American race/ethnicity with increased Alzheimer's disease rates should not be interpreted as surrogates of genetic ancestry or considered to represent African-derived populations from the developing nations such as Brazil.

  13. Relative motions of the Australian, Pacific and Antarctic plates estimated by the Global Positioning System

    NASA Technical Reports Server (NTRS)

    Larson, Kristine M.; Freymueller, Jeff

    1995-01-01

    Global Positioning System (GPS) measurements spanning approximately 3 years have been used to determine velocities for 7 sites on the Australian, Pacific and Antarctic plates. The site velocities agree with both plate model predictions and other space geodetic techniques. We find no evidence for internal deformation of the interior of the Australian plate. Wellington, New Zealand, located in the Australian-Pacific plate boundary zone, moves 20 +/- 5 mm/yr west-southwest relative to the Australian plate. Its velocity lies midway between the predicted velocities of the two plates. Relative Euler vectors for the Australia-Antarctica and Pacific-Antarctica plates agree within one standard deviation with the NUVEL-1A predictions.

  14. Understanding African American Adolescents' Identity Development: A Relational Developmental Systems Perspective

    ERIC Educational Resources Information Center

    Brittian, Aerika S.

    2012-01-01

    This article examines the development of African American adolescents' identity using a relational developmental systems theory framework, which led to the expectation that identity development is linked to both the reduction of risk behaviors and the promotion of African American adolescents' healthy development. Different personological theories…

  15. Sisters in the Struggle: African American Female Graduate Students Coping with Racism and Racism-Related

    ERIC Educational Resources Information Center

    Foster, Kelsie

    2013-01-01

    This study examined if coping was predictive of perceived racism and racism related stress of African American female graduate students. Participants were 217 African American female graduate students attending Predominantly White Institutions (PWIs), Hispanic Serving Institutions (HSIs) and Historically Black Colleges and Universities (HBCUs) and…

  16. Disparities in health-related Internet use among African American men, 2010.

    PubMed

    Mitchell, Jamie A; Thompson, Hayley S; Watkins, Daphne C; Shires, Deirdre; Modlin, Charles S

    2014-03-20

    Given the benefits of health-related Internet use, we examined whether sociodemographic, medical, and access-related factors predicted this outcome among African American men, a population burdened with health disparities. African American men (n = 329) completed an anonymous survey at a community health fair in 2010; logistic regression was used to identify predictors. Only education (having attended some college or more) predicted health-related Internet use (P < .001). African American men may vary in how they prefer to receive health information; those with less education may need support to engage effectively with health-related Internet use.

  17. Acculturation, alcohol consumption and AIDS-related risky sexual behavior among African American women.

    PubMed

    Hines, A M; Snowden, L R; Graves, K L

    1998-01-01

    The present study examined the relationship between acculturation, alcohol consumption and AIDS-related risky sexual behavior in a national probability sample of 533 African American women. Results indicated that women who were the heaviest drinkers were also the least acculturated. However, women most likely to engage in risky sexual behavior, including having multiple partners, being nonmonogamous or in a nonmonogamous relationship, and being nonmonogamous or in a nonmonogamous relationship and not using a condom consistently, were high in acculturation rather than low. Alcohol use proved related to risky sexual behavior when considered in conjunction with respondents' level of acculturation. Women at risk for contracting AIDS were not low acculturated African American women who drank heavily, but high acculturated African American women. Findings from this study extend our understanding of risk and contain implications for research and prevention efforts in the area of alcohol use and AIDS-related sexual behavior among African American women.

  18. United States-South African Relations: The Challenge for AFRICOM

    DTIC Science & Technology

    2008-03-25

    line]; available from Jane’s.com; accessed 8 December 2007. 46 Nyirabu, 27-28. 47 Kent Hughes Butts and Paul R. Thomas, The Geopolitics of Southern...Africa: South Africa as a Regional Superpower (Boulder, Colorado, West View Press, 1986)1, 170. 48 Robert S. Chase, Emily B. Hill, and Paul Kennedy...16. 70 Neethling, 59. 71 Helmoed- Romer Heitman, Jane’s, The South African Army Outlines Vision 2020 Force Design Implementation,” (19 September

  19. RELATIONAL SCHEMAS, HOSTILE ROMANTIC RELATIONSHIPS, AND BELIEFS ABOUT MARRIAGE AMONG YOUNG AFRICAN AMERICAN ADULTS

    PubMed Central

    Simons, Ronald L.; Simons, Leslie Gordon; Lei, Man Kit; Landor, Antoinette

    2011-01-01

    The present study tests a developmental model designed to explain the romantic relationship difficulties and reluctance to marry often reported for African Americans. Using longitudinal data from a sample of approximately 400 African American young adults, we examine the manner in which race-related adverse experiences during late childhood and early adolescence give rise to the cynical view of romantic partners and marriage held by many young African Americans. Our results indicate that adverse circumstances disproportionately suffered by African American youth (viz., harsh parenting, family instability, discrimination, criminal victimization, and financial hardship) promote distrustful relational schemas that lead to troubled dating relationships, and that these negative relationship experiences, in turn, encourage a less positive view of marriage. PMID:22328799

  20. RELATIONAL SCHEMAS, HOSTILE ROMANTIC RELATIONSHIPS, AND BELIEFS ABOUT MARRIAGE AMONG YOUNG AFRICAN AMERICAN ADULTS.

    PubMed

    Simons, Ronald L; Simons, Leslie Gordon; Lei, Man Kit; Landor, Antoinette

    2012-02-01

    The present study tests a developmental model designed to explain the romantic relationship difficulties and reluctance to marry often reported for African Americans. Using longitudinal data from a sample of approximately 400 African American young adults, we examine the manner in which race-related adverse experiences during late childhood and early adolescence give rise to the cynical view of romantic partners and marriage held by many young African Americans. Our results indicate that adverse circumstances disproportionately suffered by African American youth (viz., harsh parenting, family instability, discrimination, criminal victimization, and financial hardship) promote distrustful relational schemas that lead to troubled dating relationships, and that these negative relationship experiences, in turn, encourage a less positive view of marriage.

  1. Less drinking, yet more problems: understanding African American drinking and related problems.

    PubMed

    Zapolski, Tamika C B; Pedersen, Sarah L; McCarthy, Denis M; Smith, Gregory T

    2014-01-01

    Researchers have found that, compared to European Americans, African Americans report later initiation of drinking, lower rates of use, and lower levels of use across almost all age groups. Nevertheless, African Americans also have higher levels of alcohol problems than European Americans. After reviewing current data regarding these trends, we provide a theory to understand this apparent paradox as well as to understand variability in risk among African Americans. Certain factors appear to operate as both protective factors against heavy use and risk factors for negative consequences from use. For example, African American culture is characterized by norms against heavy alcohol use or intoxication, which protects against heavy use but also provides within-group social disapproval when use does occur. African Americans are more likely to encounter legal problems from drinking than European Americans, even at the same levels of consumption, perhaps thus resulting in reduced consumption but more problems from consumption. There appears to be one particular group of African Americans, low-income African American men, who are at the highest risk for alcoholism and related problems. We theorize that this effect is due to the complex interaction of residential discrimination, racism, age of drinking, and lack of available standard life reinforcers (e.g., stable employment and financial stability). Further empirical research will be needed to test our theories and otherwise move this important field forward. A focus on within-group variation in drinking patterns and problems is necessary. We suggest several new avenues of inquiry.

  2. Less Drinking, Yet More Problems: Understanding African American Drinking and Related Problems

    PubMed Central

    Zapolski, Tamika C. B.; Pedersen, Sarah L.; McCarthy, Denis M.; Smith, Gregory T.

    2013-01-01

    Researchers have found that, compared to European Americans, African Americans report later initiation of drinking, lower rates of use, and lower levels of use across almost all age groups. Nevertheless, African Americans also have higher levels of alcohol problems than European Americans. After reviewing current data regarding these trends, we provide a theory to understand this apparent paradox as well as to understand variability in risk among African Americans. Certain factors appear to operate as both protective factors against heavy use and risk factors for negative consequences from use. For example, African American culture is characterized by norms against heavy alcohol use or intoxication, which protects against heavy use but which also provides within group social disapproval when use does occur. African Americans are more likely to encounter legal problems from drinking than European Americans, even at the same levels of consumption, perhaps thus resulting in reduced consumption but more problems from consumption. There appears to be one particular group of African Americans, low-income African American men, who are at the highest risk for alcoholism and related problems. We theorize that this effect is due to the complex interaction of residential discrimination, racism, age of drinking, and lack of available standard life reinforcers (e.g., stable employment and financial stability). Further empirical research will be needed to test our theories and otherwise move this important field forward. A focus on within group variation in drinking patterns and problems is necessary. We suggest several new avenues of inquiry. PMID:23477449

  3. HIV-related Stigma among African-American Youth in the Northeast and Southeast US

    PubMed Central

    Kerr, Jelani C.; Valois, Robert F.; Diclemente, Ralph J.; Fletcher, Faith; Carey, Michael P.; Romer, Daniel; Vanable, Peter A.; Farber, Naomi

    2014-01-01

    HIV-related stigma inhibits optimal HIV prevention and treatment among African-Americans. Regional differences in HIV/AIDS prevalence may be related to stigma among young African-Americans. Baseline data (N=1,606) from an HIV prevention intervention were used to investigate regional differences in HIV-related stigma and knowledge among African-American adolescents in four midsized cities in the Northeastern and Southeastern US. Analyses indicated greater HIV-related stigma among adolescents from the southeast relative to adolescents from the northeast (F=22.23;p<0.0001). Linear regression indicated a negative relationship between HIV stigma and HIV knowledge (b=−0.65;p<0.0001). Addressing HIV/AIDS in high prevalence locales should include efforts to reduce HIV-related stigma. PMID:24402690

  4. Pacific-North America plate boundary reorganization in response to a change in relative plate motion: Offshore Canada

    NASA Astrophysics Data System (ADS)

    Rohr, K. M. M.; Tryon, A. J.

    2010-06-01

    The transition from subduction in Cascadia to the transform Queen Charlotte fault along western Canada is often drawn as a subduction zone, yet recent studies of GPS and earthquake data from northern Vancouver Island are not consistent with that model. In this paper we synthesize seismic reflection and gravity interpretations with microseismicity data in order to test models of (1) microplate subduction and (2) reorganization of the preexisting strike-slip plate boundary. We focus on the critical region of outer Queen Charlotte Sound and the adjacent offshore. On much of the continental shelf, several million years of subsidence above thin crust are a counterindicator for subduction. An undated episode of compression uplifted the southernmost shelf, but subsidence patterns offshore show that recent subduction is unlikely to be responsible. Previously unremarked near-vertical faults and a mix of extensional and compressional faults offshore indicate that strike-slip faulting has been a significant mode of deformation. Seismicity in the last 18 years is dominantly strike-slip and shows large amounts of moment release on the Revere-Dellwood fault and its overlap with the Queen Charlotte fault. The relative plate motion between the Pacific and North American plates rotated clockwise ˜6 Ma and appears to have triggered formation of an evolving array of structures. We suggest that the paleo-Queen Charlotte fault which had defined this continental margin retreated northward as offshore distributed shear and the newly formed Revere Dellwood fault propagated to the northwest.

  5. Understanding African American Adolescents’ Identity Development: A Relational Developmental Systems Perspective

    PubMed Central

    Brittian, Aerika S.

    2012-01-01

    This article examines the development of African American adolescents’ identity using a relational developmental systems theory framework, which led to the expectation that identity development is linked to both the reduction of risk behaviors and the promotion of African American adolescents’ healthy development. Different personological theories of identity development were discussed, including Erikson’s theory of psychosocial development and Marcia’s theory of identity statuses. Developmental systems theory was used to further the literature on African American adolescents’ identity development, by integrating various views of identity development as they pertain to these youth. Furthermore, the formation of many aspects of identity may be an important coping and resilience process for such youth. In addition, directions for future research are discussed, including a consideration of the complexity of diversity that exists within the African American adolescent population, and a call for more longitudinal assessments of identity development is presented. PMID:23243325

  6. Sociocultural Influences on Weight-Related Behaviors in African American Adolescents.

    PubMed

    Tate, Nutrena H; Davis, Jean E; Yarandi, Hossein N

    2015-12-01

    The purpose of this study was to examine the sociocultural factors related to weight behaviors in African American adolescents utilizing a social ecological approach. A descriptive correlational design included a sample of 145 African American adolescents. Perceived familial socialization, ethnic identity, physical activity, and eating behavior patterns were measured. Data were analyzed using descriptive statistics, Pearson product-moment correlations, and multiple regression equations. Perceived maternal socialization was significantly related to adolescent eating behaviors and physical activity whereas perceived paternal socialization was significantly related only to their physical activity. The adolescents' ethnic identity was not significantly related to their eating behaviors or physical activity. Health care providers who work with adolescents and their families can use the initial findings from this study to encourage healthy weight-related behaviors while reducing the obesity epidemic within the African American adolescent population in a developmentally appropriate and culturally sensitive manner.

  7. The Relation of Ethnic Identity, Racial Identity, and Race-Related Stress among African American College Students

    ERIC Educational Resources Information Center

    Johnson, Samon C.; Arbona, Consuelo

    2006-01-01

    The purpose of this study was to explore to what extent ethnic identity and racial identity are related constructs among African American college students by examining (a) the association of racial identity to ethnic identity and (b) the relative and unique contribution of both constructs to race-related stress. Participants were 140 college…

  8. Hantavirus Strains in East Africa Related to Western African Hantaviruses.

    PubMed

    Těšíková, Jana; Bryjová, Anna; Bryja, Josef; Lavrenchenko, Leonid A; Goüy de Bellocq, Joëlle

    2017-04-01

    Hantaviruses are RNA viruses primarily carried by rodents, soricomorphs, and bats. The data about the distribution and genetic diversity of these viruses are often limited, especially in most regions of sub-Saharan Africa. Moreover, the majority of representatives were identified in western African localities, while only three hantaviruses have been reported in East Africa to date. In this study, a total of 1866 small mammals captured between 2009 and 2014 in various countries of Eastern Africa (Ethiopia, Zambia, Mozambique, Kenya, and Tanzania) were molecularly screened for the presence of hantaviruses. Hantavirus RNA was detected in dried blood samples of the Cape pipistrelle bat (Neoromicia capensis) captured in Ethiopia and the African wood mouse (Hylomyscus endorobae) from Kenya. Phylogenetic analysis of partial genomic segments revealed that the Ethiopian sample represents a sister lineage of the Mouyassué virus (reported previously from the congeneric bat in Côte d'Ivoire), and the Kenyan sample is a sister lineage of the Sangassou virus (described from the same mouse genus in Guinea).

  9. Poverty-related stressors and HIV/AIDS transmission risks in two South African communities.

    PubMed

    Kalichman, Seth C; Simbayi, Leickness C; Jooste, Sean; Cherry, Chauncey; Cain, Demetria

    2005-06-01

    Community stress associated with poverty is related to health risks and poor health outcomes. Perceived community stress is specifically related to HIV transmission risk behaviors in the United States, but research has not examined these relationships in southern Africa, the region of the world with the highest rates of HIV infection and among the greatest poverty. Men (N=464) and women (N=531) living in impoverished adjacent communities distinguished by race (e.g., indigenous African and Coloured) completed anonymous surveys of perceptions of 10 poverty-related community stressors and measures of HIV risk-related behaviors. Indigenous African and Coloured communities differed in their perceptions of stressors, with Africans consistently viewing the 10 community stressors as more serious problems. In addition, perceived seriousness of lacking basic living resources was related to higher risk for HIV among Africans. Perceived community stress was also related to alcohol and drug use, but substance use did not mediate the association between perceived community stress and HIV risks. In the Coloured community, perceived community stressors were related to drug use, but perceived community stressors were not associated with HIV risks. These findings extend the findings of previous research to show that poverty-related stressors are associated with HIV transmission risks in some poverty-stricken communities and that these associations are not mediated by substance use.

  10. Kinship Support, Family Relations, and Psychological Adjustment among Low-Income African American Mothers and Adolescents

    ERIC Educational Resources Information Center

    Taylor, Ronald D.; Seaton, Eleanor; Dominguez, Antonio

    2008-01-01

    The association of kin social support with mothers' adjustment and family relations was assessed among 204 African American mothers and adolescents who were on average 14.45 years of age. Also examined was the association of mothers' adjustment with family relations and adolescents' adjustment. Findings revealed that kin social and emotional…

  11. Smoking Abstinence-related Expectancies among American Indians, African Americans, and Women: Potential Mechanisms of Tobacco-related Disparities

    PubMed Central

    Hendricks, Peter S.; Westmaas, J. Lee; Park, Van M. Ta; Thorne, Christopher B.; Wood, Sabrina B.; Baker, Majel R.; Lawler, R. Marsh; Hooper, Monica Webb; Delucchi, Kevin L.; Hall, Sharon M.

    2014-01-01

    Research has documented tobacco-related health disparities by race and gender. Prior research, however, has not examined expectancies about the smoking cessation process (i.e., abstinence-related expectancies) as potential contributors to tobacco-related disparities in special populations. This cross-sectional study compared abstinence-related expectancies between American Indian (n = 87), African American (n = 151), and White (n = 185) smokers, and between women (n = 231) and men (n = 270) smokers. Abstinence-related expectancies also were examined as mediators of race and gender relationships with motivation to quit and abstinence self-efficacy. Results indicated that American Indians and African Americans were less likely than Whites to expect withdrawal effects, and more likely to expect that quitting would be unproblematic. African Americans also were less likely than Whites to expect smoking cessation interventions to be effective. Compared to men, women were more likely to expect withdrawal effects and weight gain.These expectancy differences mediated race and gender relationships with motivation to quit and abstinence self-efficacy. Findings emphasize potential mechanisms underlying tobacco-related health disparities among American Indians, African Americans, and women, and suggest a number of specific approaches for targeting tobacco dependence interventions to these populations. PMID:23528192

  12. A Comparison of Faculty Dominance in U.S. and South African University Classrooms as It Relates to Cross-Cultural Relations.

    ERIC Educational Resources Information Center

    Schnell, James A.

    The South African educational system and race relations were studied in the context of effects on cross-cultural relations in the classroom. An examination of South African faculty perspectives was compared and contrasted witht U.S. faculty perspectives and was interpreted in relation to the cross-cultural relations that exist in the two…

  13. Racism-related stress, Africultural coping, and religious problem-solving among African Americans.

    PubMed

    Lewis-Coles, Ma'at E Lyris; Constantine, Madonna G

    2006-07-01

    This study explored the extent to which three types of racism-related stress (i.e., individual, institutional, and cultural) would predict the use of specific Africultural coping strategies (i.e., cognitive/emotional debriefing, spiritual-centered, collective, and ritual-centered coping) and religious problem-solving styles (i.e., self-directing, deferring, and collaborative) in a sample of 284 African American men and women. The authors found that higher institutional racism-related stress was associated with greater use of cognitive/emotional debriefing, spiritual-centered, and collective coping in African American women. Findings also indicated that higher cultural racism-related stress was predictive of lower use of self-directing religious problem-solving in African American women. Moreover, higher perceived cultural racism-related stress was related to greater use of collective coping strategies in African American men. Individual racism-related stress was not predictive of any forms of Africultural coping strategies or religious problem-solving. Implications of the findings are discussed.

  14. Dynamics of convergent plate boundaries: Insights from subduction-related serpentinite melanges from the northern edge of the Caribbean plate

    NASA Astrophysics Data System (ADS)

    García-Casco, A.

    2012-04-01

    Subduction-related rock complexes, many of them tectonic melanges, occur in the Central America-Caribbean-Andean belt. I review the lithology and P-T-t paths of HP rocks and offer interpretations and generalizations on the thermal estate of the subducting plate(s), the melange forming events, and the exhumation history of rock complexes formed in the northern branch of the Caribbean subduction zone (Cuba and nearby Guatemala and Dominican Republic; ca. 3000 km apart). These complexes contain high pressure rocks formed and exhumed at the convergent (Pacific-Atlantic) leading edge of the Caribbean plate during ca. 100 Ma (early Cretaceous-Oligocene), attesting for long lasting oceanic -followed by continental- subduction/accretion in the region. Lithologic data indicate a complex melange-forming process. In most cases, the HP rocks represent subducted MOR-related lithologies occurring as tectonic blocks within serpentinite-matrix melanges interpreted as exhumed fragments of the subduction channel(s). Most of these melanges, however, contain fragments of arc/forearc-related non metamorphic and metamorphic (low-P and high-P) sedimentary and igneous rocks. While the HP blocks of arc/forearc material indicate subduction erosion at depth, the interpretation of the LP and non-metamorphic blocks is not straight forward. Indeed, tectonic blocks of HP metamafic rocks are surrounded by antigorite-serpentinite which, in turn, is surrounded by a low-P, low-T (chrysotile-lizardite) serpentinite that makes much of the mélange. These relations indicate that the melanges represent, in fact, tectonic stacks of shallow low-T forearc serpentinite that incorporate tectonic blocks/slices of the subduction-channel (high-P, high-T serpentinite and HP metamafic blocks) and of the arc/forearc crust (low-P and non-metamorphic blocks). This picture is similar to that of HP continental margin-derived tectonic stacks containing exotic slices of antigoritite-serpentine melanges (with blocks of

  15. Characterizing the learning styles and testing the science-related attitudes of African American middle school students: Implications for the underrepresentation of African Americans in the sciences

    NASA Astrophysics Data System (ADS)

    Perine, Donald Ray

    African Americans, Hispanics, Native Americans and women are underrepresented among the population of scientists and science teachers in the United States. Specifically, the shortage of African Americans teaching math and science at all levels of the educational process and going into the many science-related fields is manifested throughout the entire educational and career structure of our society. This shortage exists when compared to the total population of African Americans in this country, the population of African American students, and to society's demand for more math and science teachers and professionals of all races. One suggestion to address this problem is to update curricular and instructional programs to accommodate the learning styles of African Americans from elementary to graduate school. There is little in the published literature to help us understand the learning styles of African American middle school students and how they compare to African American adults who pursue science careers. There is also little published data to help inform us about the relationship between learning styles of African American middle school students and their attitudes toward science. The author used a learning styles inventory instrument to identify the learning style preferences of the African American students and adults. The preferences identified describe how African American students and African American adult science professionals prefer to function, learn, concentrate, and perform in their educational and work activities in the areas of: (a) immediate environment, (b) emotionality, (c) sociological needs, and (d) physical needs. The learning style preferences for the students and adults were not significantly different in key areas of preference. A Test of Science-Related Attitudes (TOSRA) was used to measure seven distinct science-related attitudes of the middle school students. A comparison of the profile of the mean scores for the students in this study

  16. Relative Motion between the Rivera and North American Plates: Constraints from Focal Mechanisms

    NASA Astrophysics Data System (ADS)

    Suárez, Gerardo; Jaramillo, Said H.; Bandy, William

    2010-05-01

    The direction and velocity of the Rivera Plate in western Mexico relative to the North American plate has been a source of controversy. The southeastern segment of this plate boundary has been the site of one of the largest subduction events observed in Mexico during the last 100 years: the 3 June 1932 earthquake (Mw 8.2). To the northwest of the rupture zone of the 1932 event, however, there are no other known large subduction events, either from the historical or instrumental record. We analyze all focal mechanisms in this northern segment of the plate boundary to define the direction of relative motion between these two plates. The largest event occurred beneath the Tres Marias Escarpment, the earthquake of 4 December 1948. The recomputed magnitude yields Mw 6.4. This event caused widespread damage in a penal colony on the Tres Marias Islands. Although the focal mechanism of the 1948 event is not well constrained, the first arrival data collected shows reverse faulting with P axes oriented in a NE-SW direction. This mechanism coincides with other two fault plane solutions of more recent events. These mechanisms indicate reverse faulting beneath the Tres Marias Escarpment. To the northwest of the Islas Marias, in area where no clear physiographic feature defines the plate limits, we identify a group of strike-slip events, where the E-W trending nodal plane indicates right-lateral motion. These mechanisms suggest that the relative motion between Rivera and North America may be taken up by right-lateral strike slip motion. The accuracy of the locations does not allow to define in detail the geometry of this plate boundary. The slip vectors determined from these focal mechanisms are compared with the flow lines resulting from the various poles of relative motion between Rivera and North America to constrain its location.

  17. Human immunodeficiency virus-related risk behavior among African-American females.

    PubMed Central

    Cornelius, L. J.; Okundaye, J. N.; Manning, M. C.

    2000-01-01

    This study draws attention to the demographic shift in the population of HIV-infected African Americans from young, low-income, unmarried homosexual, and injecting drug users to female, heterosexual, higher income, and older persons. We used data from the 1995 Survey of Family Growth, sponsored by the National Center for Health Statistics, to examine the patterns of HIV-related risk behavior (consistent condom use, number of sexual partners, sex education in birth control methods) among African-American females. We found that only 33.3% of the African-American females had indicated that their partners always used condoms; 23.8% had seven or more lifetime sexual partners; and nearly 30% did not have any sex education in birth control methods, sexually transmitted diseases, or abstinence. In addition, African-American females who had partners who had not used condoms in the last 12 months were less likely than those who reported occasional condom use to perceive that they were infected with HIV (21.1% vs. 33.1%). These risk factors were prevalent among low-income African-American females with low socioeconomic status (SES) as well as black women with higher SES who lived in smaller cities and suburbs. These results highlight the need for HIV prevention strategies that cut across socioeconomic class, gender, sexual orientation, and place of residence. PMID:10976175

  18. Reading ability and computer-related attitudes among African American graduate students.

    PubMed

    Collins, Kathleen M T; Onwuegbuzie, Anthony J; Jiao, Qun G

    2008-06-01

    This study examined the degree that African American graduate students' reading abilities predict their attitudes toward computers and the educational use of the Internet. A canonical correlation analysis revealed that students with the lowest levels of reading ability tended to report the least computer confidence, least positive attitudes regarding computer liking, and least positive attitudes toward the educational use of the Internet. Findings of the study provide support for the hypothesis that reading ability differentially impacts African American graduate students' computer-related attitudes. The findings also suggest that reading ability may impede African American students' acquisition of computer and Internet skills and may negatively impact their achievement levels in graduate courses requiring computer-based skills.

  19. Understanding the African-American Student Experience in Higher Education through a Relational Dialectics Perspective

    ERIC Educational Resources Information Center

    Simmons, Jake; Lowery-Hart, Russell; Wahl, Shawn T.; McBride, M. Chad

    2013-01-01

    In this study, we sought to understand African-American students' higher-education experiences in predominantly White universities. We utilized Baxter's relational dialectics theory to study components of focus-group discussions in order to understand the discourse and meaning-making process of participants. Our findings provide insight into the…

  20. The Relation of Racial Identity and Racial Socialization to Coping with Discrimination among African American Adolescents.

    ERIC Educational Resources Information Center

    Scott, Lionel D.

    2003-01-01

    Surveyed African American high school students regarding whether strategies they used to cope with perceived discrimination related to their racial identity and racial socialization. The degree to which race was central to self-concept and identity was unrelated to both approach and avoidance strategies. Frequency of receiving socialization…

  1. Racism-Related Stress and Ethnic Identity as Determinants of African American College Students' Career Aspirations

    ERIC Educational Resources Information Center

    Tovar-Murray, Darrick; Jenifer, Ericka S.; Andrusyk, Jara; D'Angelo, Ryan; King, Tia

    2012-01-01

    Drawing primarily on the construct of psychological buffer, the purpose of this study was to explore the extent to which racism-related stress and ethnic identity are determinants of career aspirations. A total of 163 African American college students from a predominately White Midwestern university participated in the study. A moderation…

  2. African American Career Aspirations: Examining the Relative Influence of Internalized Racism

    ERIC Educational Resources Information Center

    Brown, Danice L.; Segrist, Daniel

    2016-01-01

    The present study examined the relative influence of aspects of internalized racism on the career aspirations of a sample of African American adults. Participants (N = 315), ranging in age from 18 to 62 years, completed measures of internalized racism and career aspirations online. A hierarchical multiple regression analysis was conducted to…

  3. Mechanisms of Family Impact on African American Adolescents' HIV-Related Behavior

    ERIC Educational Resources Information Center

    Kogan, Steven M.; Brody, Gene H.; Gibbons, Frederick X.; Chen, Yi-fu; Grange, Christina M.; Simons, Ronald L.; Gerrard, Meg; Cutrona, Carolyn E.

    2011-01-01

    A longitudinal model that tested mediating pathways between protective family processes and HIV-related behavior was evaluated with 195 African American youth. Three waves of data were collected when the youth were 13, 15, and 19 years old. Evidence of mediation and temporal priority were assessed for 3 constructs: academic engagement, evaluations…

  4. Ring of Silence: African American Women's Experiences Related to Their Breasts and Breast Cancer Screening

    ERIC Educational Resources Information Center

    Thomas, Eileen

    2006-01-01

    The purpose of this study was to explore women's memories and feelings concerning their breasts and breast cancer screening experiences in relation to their current breast cancer screening behaviors. Twelve African American women shared stories that were generated in written narratives and individual interviews. Two core themes emerged from the…

  5. Relative Spousal Earnings and Marital Happiness among African American and White Women

    ERIC Educational Resources Information Center

    Furdyna, Holly E.; Tucker, M. Belinda; James, Angela D.

    2008-01-01

    The distinctive economic histories of African American and White wives suggest that involvement in household income production holds contextually situated unique meanings for these groups. Yet research has not addressed racial differences in the effects of relative earnings on marital well-being. Surveying 431 employed wives in 21 U.S. cities, we…

  6. HIV-related stigma among African, Caribbean, and Black youth in Windsor, Ontario.

    PubMed

    Mihan, Robert; Kerr, Jelani; Maticka-Tyndale, Eleanor

    2016-01-01

    HIV-related stigma has been shown to undermine prevention, care, treatment, and the well-being of people living with HIV. A disproportion burden of HIV infection, as well as elevated levels of HIV-related stigma, is evidenced in sub-Saharan African (SSA) and African-diasporic populations. This study explores factors that influence HIV-related stigma among 16- to 25-year-old youth residing in a Canadian city who identify as African, Caribbean, or Black. Stigma, as rooted in cultural norms and beliefs and related social institutions, combined with insights from research on stigma in SSA and African-diasporic populations, guided the development of a path analytic structural equation model predicting levels of HIV-related stigmatizing attitudes. The model was tested using survey responses of 510 youth to estimate the direct and indirect influences of ethno-religious identity, religious service attendance, time in Canada, HIV/AIDS knowledge, HIV-testing history, sexual health service contact, and gender on HIV-related stigma. Statistically significant negative associations were found between levels of stigma and knowledge and HIV-testing history. Ethno-religious identity and gender had both direct and indirect effects on stigma. African-Muslim participants had higher levels of stigma, lower knowledge, and were less likely to have been tested for HIV infection than other ethno-religious groups. Male participants had higher levels of stigma and lower knowledge than women. Time in Canada had only indirect effects on stigma, with participants in Canada for longer periods having higher knowledge and less likely to have been tested than more recent arrivals. While the strength of the effect of knowledge on stigmatizing attitudes in this research is consistent with other research on stigma and evaluations of stigma-reduction programs, the path analytic results provide additional information about how knowledge and HIV-testing function as mediators of non

  7. Relative Motion of Nubia Plate with Respect to West Africa, Congo and Kalahari Cratons

    NASA Astrophysics Data System (ADS)

    Njoroge, M. W.

    2015-12-01

    The Nubia plate is normally considered to be a rigid plate and as such used in the realization of terrestrial reference frame. Gondwana breakup plate reconstruction, the Cameroon volcanic line, seismicity, and the morphology of the Okavango rift zone (ORZ) suggest the presence of internal deformation within the Nubia plate. To test this hypothesis, six different reference frames were developed from the velocity field of three individual regions (West, Central and South), and of different combinations of them (West+Central, South+Central, and Nubia as a whole). The residual velocities with respect to these references frame help us understand the presence of the relative motion between the different regions thus the stability of the plate. To realize the reference frames, all the publicly available GPS data within the "stable" Nubia plate was processed. Given the small relative velocity, it is important to eliminate eventual biases in the analysis and to have good estimates of uncertainty of the observed velocities. For this reason, velocities were analyzed, and rate uncertainties computed using the Allan variance of rate (AVR) technique, accounting for colored noise. Although geological and geophysical studies indicate the possibility of internal deformation within Nubia, the results of this study shows that the current GPS network is not capable to identify intraplate deformation and within uncertainties Nubia is a single plate. As final note, both the color of the noise and the amplitude of the annual signal of each time series as function of latitude and climatic region were analyzed. The study shows that the noise is approximately flicker for all the good stations independently of the location. On the contrary, the amplitude of the annual signal is strongly dependent on the climate of the regions.

  8. Relative Motion Between the Rivera and North American Plates Determined from the Slip Directions of Earthquakes

    NASA Astrophysics Data System (ADS)

    Suárez, Gerardo; Jaramillo, Said H.; Bandy, W. L.

    2013-12-01

    So far, the direction and rate of relative motion between the Rivera and the North American plates (RIV-NAM) has been determined by the combination of two Euler poles: Rivera (RIV), with respect to Pacific (PAC), and PAC with respect to North America. Here, we estimate the relative motion of this plate pair (RIV-NAM) assuming that the horizontal projection of the direction of slip of the earthquakes occurring on the RIV-NAM boundaries reflect their relative plate motion. A catalog of earthquakes for which focal mechanisms are reported since 1976 is used in the analysis. Earthquakes were considered in the three segments of the RIV-NAM plate boundary: the subduction zone of the Rivera plate beneath the Jalisco block, the Tres Marias Escarpment and the events associated with the Tamayo Fracture Zone. The best fitting Euler pole is determined using a grid search of 64 potential poles. The slip direction predicted for each grid point is compared to the slip direction of the focal mechanisms of the earthquakes on the plate boundary. The best fitting Euler pole, determined in a root mean square sense (RMS), is located at 21.8°N, 107.6°W. A rate of rotation of 5.3°/year is estimated assuming the seismic earthquake cycle of the 1932 and 1995 great earthquakes represents a lower bound of the rate of plate motion in the subduction zone. The best fitting Euler pole shows that the subduction of the Rivera plate takes place in a direction perpendicular to the trench with a relative velocity of 4.3 cm/year, offshore Manzanillo. The rate of relative motion RIV-NAM decreases from SE to NW. North of approximately 21°N, the subduction of the Rivera plate becomes oblique to the trench and the relative velocity between the two plates decreases to an average of 1.9 cm/year. This slow rate of convergence may explain the rapid decrease of seismicity in the trench and the apparent absence of large earthquakes in this region. In the Tres Marias Escarpment, our best-fitting pole suggests

  9. Tectonic implications of post-30 Ma Pacific and North American relative plate motions

    USGS Publications Warehouse

    Bohannon, R.G.; Parsons, T.

    1995-01-01

    The Pacific plate moved northwest relative to North America since 42 Ma. The rapid half rate of Pacific-Farallon spreading allowed the ridge to approach the continent at about 29 Ma. Extinct spreading ridges that occur offshore along 65% of the margin document that fragments of the subducted Farallon slab became captured by the Pacific plate and assumed its motion proper to the actual subduction of the spreading ridge. This plate-capture process can be used to explain much of the post-29 Ma Cordilleran North America extension, strike slip, and the inland jump of oceanic spreading in the Gulf of California. Much of the post-29 Ma continental tectonism is the result of the strong traction imposed on the deep part of the continental crust by the gently inclined slab of subducted oceanic lithosphere as it moved to the northwest relative to the overlying continent. -from Authors

  10. Comparison of Infant Sleep Practices in African-American and US Hispanic Families: Implications for Sleep-Related Infant Death.

    PubMed

    Mathews, Anita A; Joyner, Brandi L; Oden, Rosalind P; Alamo, Ines; Moon, Rachel Y

    2015-06-01

    African-American and Hispanic families share similar socioeconomic profiles. Hispanic rates of sleep-related infant death are four times lower than African-American rates. We conducted a cross-sectional, multi-modal (surveys, qualitative interviews) study to compare infant care practices that impact risk for sleep-related infant death in African-American and Hispanic families. We surveyed 422 African-American and 90 Hispanic mothers. Eighty-three African-American and six Hispanic mothers participated in qualitative interviews. African-American infants were more likely to be placed prone (p < 0.001), share the bed with the parent (p < 0.001), and to be exposed to smoke (p < 0.001). Hispanic women were more likely to breastfeed (p < .001), while African-American women were more knowledgeable about SIDS. Qualitative interviews indicate that, although African-American and Hispanic parents had similar concerns, behaviors differed. Although the rationale for infant care decisions was similar for African-American and Hispanic families, practices differed. This may help to explain the racial/ethnic disparity seen in sleep-related infant deaths.

  11. Seismic and Geodynamic Constraints on Compositional Heterogeneity in the Lower Mantle: Implications for Deeply-Rooted Hot Upwellings Under the African and Pacific Plates

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Glisovic, P.; Rowley, D. B.; Simmons, N. A.; Grand, S. P.; Lu, C.

    2014-12-01

    We present the results of a series of tests that probe the possible existence of compositionally distinct material in the central core of the LLSVPs under the African and Pacific plates using tomography-based mantle flow models that employ several independently-derived viscosity profiles (Mitrovica & Forte 2004, Behn et al. 2004, Steinberger & Calderwood 2006, Forte et al. 2010). We also consider four global tomography models derived from seismic shear velocity data alone (Grand 2002, Panning & Romanowicz 2006, Kustowski et al. 2008, Ritsema et al. 2011). The possible combinations of viscosity and tomography models yield 16 different tests for compositional heterogeneity inside the LLSVPs. In all tests we begin with a mineral physical scaling between lower-mantle shear velocity and density anomalies that assumes thermal effects are dominant everywhere, including within the LLSVPs. We find it is not possible, in any of the tests, to obtain a satisfactory fit to surface geodynamic data, especially the global, long-wavelength gravity anomalies and space-geodetic inferences of excess CMB flattening with a purely thermal interpretation of lower-mantle heterogeneity. If we introduce compositionally-distinct material in the central portions of the LLSVPs, all tests show a notable improvement in the fit to the gravity anomaly and CMB ellipticity data. An optimal reconciliation of the gravity and CMB data is obtained by extending compositional heterogeneity upwards, with maximum-amplitude in the seismic D"-layer and tapering off to negligible values in the mid-mantle. A robust assessment of the dynamical impact of this deeply-rooted compositional heterogeneity is obtained with maps of "mean" convective flow, by averaging the results of all 16 test cases. We find (see map below) dominant lower-mantle upwellings below the axis of the East Pacific Rise (EPR), and under the Caroline Islands in the Western Pacific. Under the African plate we find large-scale upwellings under the

  12. Paleocene emergence of elephant relatives and the rapid radiation of African ungulates.

    PubMed

    Gheerbrant, Emmanuel

    2009-06-30

    Elephants are the only living representatives of the Proboscidea, a formerly diverse mammalian order whose history began with the 55-million years (mys) old Phosphatherium. Reported here is the discovery from the early late Paleocene of Morocco, ca. 60 mys, of the oldest and most primitive elephant relative, Eritherium azzouzorum n.g., n.sp., which is one of the earliest known representatives of modern placental orders. This well supported stem proboscidean is extraordinarily primitive and condylarth-like. It provides the first dental evidence of a resemblance between the proboscideans and African ungulates (paenungulates) on the one hand and the louisinines and early macroscelideans on the other. Eritherium illustrates the origin of the elephant order at a previously unknown primitive stage among paenungulates and "ungulates." The primitive morphology of Eritherium suggests a recent and rapid paenungulate radiation after the Cretaceous-Tertiary boundary, probably favoured by early endemic African paleoecosystems. At a broader scale, Eritherium provides a new old calibration point of the placental tree and supports an explosive placental radiation. The Ouled Abdoun basin, which yields the oldest known African placentals, is a key locality for elucidating phylogeny and early evolution of paenungulates and other related endemic African lineages.

  13. Plate motion

    SciTech Connect

    Gordon, R.G. )

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  14. The role of the African-American physician in reducing traffic-related injury and death among African Americans: consensus report of the National Medical Association.

    PubMed Central

    Daniels, Fernando; Moore, Wayne; Conti, Christopher; Norville Perez, Lucille C.; Gaines, Beverly M.; Hood, Rodney G.; Swain, Ian J. J.; Williams, Rudolph; Burgess, Chaka T.

    2002-01-01

    ISSUE: Traffic-related injuries and fatalities disproportionately affect the African American community. These high rates of traffic-related death and injury among African Americans manifest in multiple areas of traffic safety, including: Failure to use seat belts and child restraints. High incidence of alcohol-impaired driving. Failure to follow child passenger and seat belt safety laws and recommendations. High rates of pedestrian accidents, ofen brought on by impairments of drivers and/or pedestrians. Research indicates that national public information campaigns, with general messages only slightly modified for African American audiences, have not been culturally appropriate or effective in changing traffic safety behavior. In addition, traditional distribution mechanisms for these messages have not effectively reached the target population. Evidence suggests that in the African American community, there is a pervasive lack of knowledge of the devastating impact of traffic-related accidents on the overall health status of the community. This lack of information has resulted in a tragic cycle, in which parents fail to model safe operation of motor vehicles, and generation after generation copy this behavior, increasing the community's vulnerability to serious injuries and untimely deaths. This trend toward improper traffic safety habits among African Americans persists despite federal, state and local laws to enforce and promote sound traffic safety practices. OBJECTIVE: To study the existence of disparities in traffic-related injury and death among African Americans and to determine what kinds of traffic safety messages and campaigns will be effective in encouraging African Americans to respond to safety laws in sufficient numbers to reduce the disproportionately high rate of injury and death. Traffic safety issues were examined to effectively recommend policy, address barriers, best practices, and intervention strategies for the National Medical Association

  15. Knowledge, Beliefs and Behaviours Related to STD Risk, Prevention, and Screening among a Sample of African American Men and Women

    ERIC Educational Resources Information Center

    Uhrig, Jennifer D.; Friedman, Allison; Poehlman, Jon; Scales, Monica; Forsythe, Ann

    2014-01-01

    Objective: Current data on sexually transmitted disease (STD) among African Americans show significant racial/ethnic disparities. The purpose of this study was to explore knowledge, attitudes, beliefs, and behaviours related to STD risk, prevention, and testing among African American adults to help inform the development of a health communication…

  16. Current Plate Motion Relative to the Hotspots and to the Mantle

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Gordon, R. G.; Argus, D.; Demets, C.; Kreemer, C. W.

    2010-12-01

    We present several new global sets of angular velocities of the plates relative to the deeper mantle. A starting point for our estimate of plate motion relative to the hotspots is HS3, a hotspot data set developed by Gripp & Gordon [2002], which consists of two volcanic propagation rates and eleven segment trends from the Pacific, Nazca, South America, and North America plates. Due to the bias (argon loss) inherent in K-Ar measurements, the volcanic ages in HS3 are probably systematically too young and the volcanic propagation rates are thus probably biased (i.e., they are too high) [Morgan & Phipps Morgan, 2007]. Here we use the difference between an astrogeochronologic-based geomagnetic reversal time scale [Gradstein et al. 2004] and a K-Ar-based geomagnetic reversal time scale [Harland et al. 1982] as a proxy to estimate the recalibration required for K-Ar measurements. This recalibration of K-Ar ages reduces the volcanic propagation rates of the Hawaii hotspot track and the Society hotspot track by 8% and 6% respectively. We incorporate these revised volcanic propagation rates into the HS3B data set, which is merely HS3 corrected for this bias. We combine the HS3B data set with the MORVEL global set of plate relative angular velocities [DeMets et al., 2010] to determine HS3B-MORVEL, a new global set of plate angular velocities relative to the hotspots. Unsurprisingly, the motion of the Pacific plate relative to the hotspots is slower in HS3B-MORVEL than in HS3-NUVEL1A. Because the orientations of seismic anisotropy inferred from shear-wave splitting may in many places indicate the direction of motion of lithosphere relative to the deeper mantle, Kreemer [2009] compiled a data set of 474 shear-wave splitting data, which we refer to as the SKS data set. When we invert these data in a manner similar to his, but using the MORVEL relative angular velocities, we find that the azimuth residuals of SKS-MORVEL are strongly correlated within each plate and do not have

  17. Is the number of antennal plate organs (sensilla placodea) greater in hygienic than in non-hygienic Africanized honey bees?

    PubMed

    Gramacho, Kátia Peres; Gonçalves, Lionel Segui; Stort, Antônio Carlos; Noronha, Adriana Backx

    2003-09-30

    Hygienic behavior is a desirable trait in honey bees (Apis mellifera L.), as hygienic bees quickly remove diseased brood, interrupting the infectious cycle. Hygienic lines of honey bees appear to be more sensitive to the odors of dead and diseased honey bee brood, and Africanized honey bees are generally more hygienic than are European honey bees. We compared the number of sensilla placodea, antennal sensory structures involved in the perception of odor, in 10 bees from each of six hygienic and four non-hygienic colonies of Africanized honey bees. The sensilla placodea of three of the terminal segments (flagellomeres) of the right antenna of each bee were counted with a scanning electron microscope. There were no significant differences in the mean numbers of sensilla placodea between the hygienic and non-hygienic bees, though the variance was higher in the hygienic group. Flagellomere 4 had significantly more sensilla placodea than flagellomeres 6 and 8. However, there was no significant difference between the other two flagellomeres. As hygienic bees are capable of identifying dead, injured, or infested brood inside a capped brood cell, sensilla placodea probably have an important role in enabling worker bees to sense sick brood. However, we did not find greater numbers of this sensory structure in the antennae of hygienic, compared to non-hygienic Africanized honey bees.

  18. Impact of disaster-related mortality on gross domestic product in the WHO African Region.

    PubMed

    Kirigia, Joses M; Sambo, Luis G; Aldis, William; Mwabu, Germano M

    2004-03-15

    BACKGROUND: Disaster-related mortality is a growing public health concern in the African Region. These deaths are hypothesized to have a significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. METHODS: The impact of disaster-related mortality on GDP was estimated using double-log econometric model and cross-sectional data on various Member States in the WHO African Region. The analysis was based on 45 of the 46 countries in the Region. The data was obtained from various UNDP and World Bank publications. RESULTS: The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The above-mentioned explanatory variables were found to have a statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.01828. CONCLUSIONS: We have demonstrated that disaster-related mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increased educational enrolment, they should always keep in mind that investments made in the strengthening of national capacity to mitigate the effects of national disasters expeditiously and effectively will yield significant economic returns.

  19. Impact of disaster-related mortality on gross domestic product in the WHO African Region

    PubMed Central

    Kirigia, Joses M; Sambo, Luis G; Aldis, William; Mwabu, Germano M

    2004-01-01

    Background Disaster-related mortality is a growing public health concern in the African Region. These deaths are hypothesized to have a significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. Methods The impact of disaster-related mortality on GDP was estimated using double-log econometric model and cross-sectional data on various Member States in the WHO African Region. The analysis was based on 45 of the 46 countries in the Region. The data was obtained from various UNDP and World Bank publications. Results The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The above-mentioned explanatory variables were found to have a statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.01828. Conclusions We have demonstrated that disaster-related mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increased educational enrolment, they should always keep in mind that investments made in the strengthening of national capacity to mitigate the effects of national disasters expeditiously and effectively will yield significant economic returns. PMID:15113453

  20. Emotional adjustment and distressed interpersonal relations among low-income African American mothers: moderating effects of demanding kin relations.

    PubMed

    Taylor, Ronald D; Budescu, Mia

    2013-01-01

    Association of mothers' emotional adjustment and negative kin relations with distressed interpersonal relations was examined. Among 115 low-income African American mothers, relationship of depressive symptoms, self-esteem, and demanding kin relations with psychological control and stressful interpersonal relations was assessed. Depressive symptoms and demanding kin relations were positively associated with mothers' use of psychological control in parenting. Interaction of self-esteem with demanding kin relations revealed that self-esteem was negatively associated with psychological control for mothers with high-demanding kin relations but not for mothers with low-demanding kin relations. Mothers' depressive symptoms and demanding kin relations were positively associated with their stressful interpersonal relations. Findings were discussed in terms of the need for research on the beneficial and detrimental aspects of families' social network.

  1. Perceived Racial Discrimination and Negative-Mood–Related Drinking Among African American College Students

    PubMed Central

    O’hara, Ross E.; Armeli, Stephen; Scott, Denise M.; Covault, Jonathan; Tennen, Howard

    2015-01-01

    Objective: Research consistently shows a positive association between racial discrimination and problematic alcohol use among African Americans, but little is known about the micro-processes linking this pernicious form of stress to drinking. One possibility is that the cumulative effects of discrimination increase individuals’ likelihood of negative-mood–related drinking. In the current study, we examined whether individual differences in lifetime perceived racial discrimination among African American college students moderate relations between daily negative moods and evening alcohol consumption in both social and nonsocial contexts. Method: Data came from an online daily diary study of 441 African Americans (58% female) enrolled at a historically black college/university. Lifetime discrimination was measured at baseline. For 30 days, students reported the number of drinks they consumed the night before both socially and nonsocially, as well as their daytime level of negative mood. Results: In support of the hypotheses, only men who reported higher (vs. lower) lifetime discrimination showed a positive association between daily negative mood and that evening’s level of nonsocial drinking. Contrary to expectation, women who reported higher (vs. lower) discrimination showed a negative association between daily negative mood and nonsocial drinking. Neither daily negative mood nor lifetime discrimination predicted level of social drinking. Conclusions: These findings provide further evidence that the cumulative impact of racial discrimination may produce a vulnerability to negative-mood–related drinking—but only for African American men. Importantly, these effects emerged only for nonsocial drinking, which may further explain the robust association between discrimination and problematic alcohol use. PMID:25785798

  2. Permian and Pennsylvanian tectonic events in eastern California in relation to major plate motions

    SciTech Connect

    Stevens, C.H.; Sedlock, R. ); Stone, P. )

    1993-04-01

    Northwest-trending basins cutting across older northeast-trending facies belts in eastern California opened by Middle Pennsylvanian time and continued to develop and expand into the Early Permian. Basin development was accompanied by east-vergent thrust-faulting in the Early Permian and was followed by development of northeast-trending folds and regional uplift in middle and Late Permian time. These events have been considered products of long-tern sinistral truncation of the western North American continental margin. Later, in the Late Permian, extensional faulting created small northeast-trending basins in which deposition of terrestrial and shallow-marine rocks occurred. The author consider all late Paleozoic tectonism in eastern California to have been driven by plate interactions along the western margin of North America and to be only indirectly related to the late Paleozoic collision between North America and Gondwana. They propose that the truncated part of North America was part of the Paleo-pacific plate. In Nevada the margin of this plate, along which the Havallah assemblage eventually was emplaced, was convergent, but in California the margin bent sharply and became transform. This fault continued as the Mojave-Sonora mega-shear into Mexico where the oceanic part of the Paleopacific plate was subducted under Gondwana, forming an extensive arc now represented by rocks in S. America.

  3. The proportionality between relative plate velocity and seismicity in subduction zones

    NASA Astrophysics Data System (ADS)

    Ide, S.

    2013-12-01

    Seismic activity differs among subduction zones due to various factors such as relative plate velocity, temperature, stress, and subducting materials. Relative plate velocity has a direct control on tectonic deformation and an overall correlation with seismicity has been suggested, as a global average or for large regions. Here I show a positive correlation between relative plate velocity and seismicity by estimating the background seismicity rate for 117 sections of subduction zones worldwide using the epidemic type aftershock sequence (ETAS) model. The background rate is stably estimated even for the period following M9-class earthquakes in Chile and Japan. A prominent proportional relationship is evident in the southwestern Pacific Ocean. Given that M9-class earthquakes occur independently of one another, the lack of M9 earthquakes in the southwestern Pacific Ocean over the last century is difficult to explain by chance. On the other hand, some subduction zones have extremely low background seismicity, and have experienced very large earthquakes. Slow earthquakes have been discovered in many of these quiet zones. Thus, this proportionality relation may be useful in assessing the seismic risk in subduction zones worldwide between two apparently confusing end members: 'active and moderate' and 'quiet and extreme'.

  4. Statistical tests of additional plate boundaries from plate motion inversions

    NASA Technical Reports Server (NTRS)

    Stein, S.; Gordon, R. G.

    1984-01-01

    The application of the F-ratio test, a standard statistical technique, to the results of relative plate motion inversions has been investigated. The method tests whether the improvement in fit of the model to the data resulting from the addition of another plate to the model is greater than that expected purely by chance. This approach appears to be useful in determining whether additional plate boundaries are justified. Previous results have been confirmed favoring separate North American and South American plates with a boundary located beween 30 N and the equator. Using Chase's global relative motion data, it is shown that in addition to separate West African and Somalian plates, separate West Indian and Australian plates, with a best-fitting boundary between 70 E and 90 E, can be resolved. These results are generally consistent with the observation that the Indian plate's internal deformation extends somewhat westward of the Ninetyeast Ridge. The relative motion pole is similar to Minster and Jordan's and predicts the NW-SE compression observed in earthquake mechanisms near the Ninetyeast Ridge.

  5. The timing of Mediterranean sapropel deposition relative to insolation, sea-level and African monsoon changes

    NASA Astrophysics Data System (ADS)

    Grant, Katharine; Grimm, Rosina; Mikolajewicz, Uwe; Marino, Gianluca; Rohling, Eelco

    2016-04-01

    The periodic deposition of organic rich layers or 'sapropels' in eastern Mediterranean sediments can be linked to orbital-driven changes in the strength and location of (east) African monsoon precipitation. Sapropels are therefore an extremely useful tool for establishing orbital chronologies, and for providing insights about African monsoon variability on long timescales. However, the link between sapropel formation, insolation variations, and African monsoon 'maxima' is not straightforward because other processes (notably, sea-level rise) may have contributed to their deposition, and because there are uncertainties about monsoon-sapropel phase relationships. For example, different phasings are observed between Holocene and early Pleistocene sapropels, and between proxy records and model simulations. To address these issues, we have established geochemical and ice-volume-corrected planktonic foraminiferal stable isotope records for sapropels S1, S3, S4, and S5 in core LC21 from the southern Aegean Sea. The records have a radiometrically constrained chronology that has already been synchronised with the Red Sea relative sea-level record, and this allows us to examine in detail the timing of sapropel deposition relative to insolation, sea-level, and African monsoon changes. Our records suggest that the onset of sapropel deposition and monsoon run-off was near synchronous, yet insolation-sapropel/monsoon phasings varied, whereby monsoon/sapropel onset was relatively delayed (with respect to insolation maxima) after glacial terminations. We suggest that large meltwater discharges into the North Atlantic modified the timing of sapropel deposition by delaying the timing of peak African monsoon run-off. Hence, the previous assumption of a systematic 3-kyr lag between insolation maxima and sapropel midpoints may lead to overestimated insolation-sapropel phasings. We also surmise that both monsoon run-off and sea-level rise were important buoyancy-forcing mechanisms for

  6. Related strains of African swine fever virus with different virulence: genome comparison and analysis.

    PubMed

    Portugal, Raquel; Coelho, João; Höper, Dirk; Little, Nicole S; Smithson, Chad; Upton, Chris; Martins, Carlos; Leitão, Alexandre; Keil, Günther M

    2015-02-01

    Two strains of African swine fever virus (ASFV), the high-virulence Lisboa60 (L60) and the low-virulence NH/P68 (NHV), which have previously been used in effective immunization/protection studies, were sequenced. Both were isolated in Portugal during the 11-year period after the introduction of ASFV to the European Continent in 1957. The predicted proteins coded by both strains were compared, and where differences were found these were also compared to other strains of known virulence. This highlighted several genes with significant alterations in low-virulence strains of ASFV that may constitute virulence factors, several of which are still uncharacterized regarding their function. Phylogenetic analysis grouped L60 and NHV closest to other P72 genotype I ASFV strains from Europe and West Africa, consistent with the assumed West African origin of all European strains. Interestingly, a relatively lower genomic identity exists between L60 and NHV, both isolated in a similar geographical location 8 years apart, than with other European and west African strains isolated subsequently and in more distant locations. This may reflect the intensive passage in tissue culture, during the early 1960s, of a Portuguese isolate to obtain an attenuated vaccine, which may have led to NHV. This study contributes to a better understanding of the evolution of ASFV, and defines additional potential virulence genes for future studies of pathogenesis towards the development of effective vaccines.

  7. The timing of Mediterranean sapropel deposition relative to insolation, sea-level and African monsoon changes

    NASA Astrophysics Data System (ADS)

    Grant, K. M.; Grimm, R.; Mikolajewicz, U.; Marino, G.; Ziegler, M.; Rohling, E. J.

    2016-05-01

    The Mediterranean basin is sensitive to global sea-level changes and African monsoon variability on orbital timescales. Both of these processes are thought to be important to the deposition of organic-rich sediment layers or 'sapropels' throughout the eastern Mediterranean, yet their relative influences remain ambiguous. A related issue is that an assumed 3-kyr lag between boreal insolation maxima and sapropel mid-points remains to be tested. Here we present new geochemical and ice-volume-corrected planktonic foraminiferal stable isotope records for sapropels S1 (Holocene), S3, S4, and S5 (Marine Isotope Stage 5) in core LC21 from the southern Aegean Sea. The records have a radiometrically constrained chronology that has already been synchronised with the Red Sea relative sea-level record, and this allows detailed examination of the timing of sapropel deposition relative to insolation, sea-level, and African monsoon changes. We find that sapropel onset was near-synchronous with monsoon run-off into the eastern Mediterranean, but that insolation-sapropel/monsoon phasings were not systematic through the last glacial cycle. These latter phasings instead appear to relate to sea-level changes. We propose that persistent meltwater discharges into the North Atlantic (e.g., at glacial terminations) modified the timing of sapropel deposition by delaying the timing of peak African monsoon run-off. These observations may reconcile apparent model-data offsets with respect to the orbital pacing of the African monsoon. Our observations also imply that the previous assumption of a systematic 3-kyr lag between insolation maxima and sapropel midpoints may lead to overestimated insolation-sapropel phasings. Finally, we surmise that both sea-level rise and monsoon run-off contributed to surface-water buoyancy changes at times of sapropel deposition, and their relative influences differed per sapropel case, depending on their magnitudes. Sea-level rise was clearly important for

  8. Genetic architecture of age-related cognitive decline in African Americans

    PubMed Central

    Raj, Towfique; Chibnik, Lori B.; McCabe, Cristin; Wong, Andus; Replogle, Joseph M.; Yu, Lei; Gao, Sujuan; Unverzagt, Frederick W.; Stranger, Barbara; Murrell, Jill; Barnes, Lisa; Hendrie, Hugh C.; Foroud, Tatiana; Krichevsky, Anna; Bennett, David A.; Hall, Kathleen S.; Evans, Denis A.

    2016-01-01

    Objective: To identify genetic risk factors associated with susceptibility to age-related cognitive decline in African Americans (AAs). Methods: We performed a genome-wide association study (GWAS) and an admixture-mapping scan in 3,964 older AAs from 5 longitudinal cohorts; for each participant, we calculated a slope of an individual's global cognitive change from neuropsychological evaluations. We also performed a pathway-based analysis of the age-related cognitive decline GWAS. Results: We found no evidence to support the existence of a genomic region which has a strongly different contribution to age-related cognitive decline in African and European genomes. Known Alzheimer disease (AD) susceptibility variants in the ABCA7 and MS4A loci do influence this trait in AAs. Of interest, our pathway-based analyses returned statistically significant results highlighting a shared risk from lipid/metabolism and protein tyrosine signaling pathways between cognitive decline and AD, but the role of inflammatory pathways is polarized, being limited to AD susceptibility. Conclusions: The genetic architecture of aging-related cognitive in AA individuals is largely similar to that of individuals of European descent. In both populations, we note a surprising lack of enrichment for immune pathways in the genetic risk for cognitive decline, despite strong enrichment of these pathways among genetic risk factors for AD. PMID:28078323

  9. An Examination of Color-Blind Racism and Race-Related Stress among African American Undergraduate Students

    ERIC Educational Resources Information Center

    Coleman, M. Nicole; Chapman, Stephanie; Wang, David C.

    2013-01-01

    This study examined the role of color-blind racial ideology among a sample of 152 African American undergraduate students in relation to race-related stress. We hypothesized that those who endorsed relatively higher color-blind racial attitudes would experience greater race-related stress because experiences with racism would be interpreted as…

  10. Detection of novel sequences related to african Swine Fever virus in human serum and sewage.

    PubMed

    Loh, Joy; Zhao, Guoyan; Presti, Rachel M; Holtz, Lori R; Finkbeiner, Stacy R; Droit, Lindsay; Villasana, Zoilmar; Todd, Collin; Pipas, James M; Calgua, Byron; Girones, Rosina; Wang, David; Virgin, Herbert W

    2009-12-01

    The family Asfarviridae contains only a single virus species, African swine fever virus (ASFV). ASFV is a viral agent with significant economic impact due to its devastating effects on populations of domesticated pigs during outbreaks but has not been reported to infect humans. We report here the discovery of novel viral sequences in human serum and sewage which are clearly related to the asfarvirus family but highly divergent from ASFV. Detection of these sequences suggests that greater genetic diversity may exist among asfarviruses than previously thought and raises the possibility that human infection by asfarviruses may occur.

  11. A novel human polyomavirus closely related to the african green monkey-derived lymphotropic polyomavirus.

    PubMed

    Scuda, Nelly; Hofmann, Jörg; Calvignac-Spencer, Sébastien; Ruprecht, Klemens; Liman, Peter; Kühn, Joachim; Hengel, Hartmut; Ehlers, Bernhard

    2011-05-01

    We identified a novel human polyomavirus from a kidney transplant patient under immunosuppressive treatment, by use of a generic PCR. The genome of the virus was completely amplified and sequenced. In phylogenetic analyses, it appeared as the closest relative to the African green monkey-derived lymphotropic polyomavirus (LPV). Further investigation of clinical samples from immunocompromised patients with specific nested PCR revealed additional positive samples, indicating that the virus naturally infects humans. The virus was tentatively named human polyomavirus 9 (HPyV9). The previously observed seroreactivity to LPV in human populations might find a partial explanation in the circulation of HPyV9.

  12. New Constraints on Baja California-North America Relative Plate Motion Since 11 Ma

    NASA Astrophysics Data System (ADS)

    Bennett, S. E.; Skinner, L. A.; Darin, M. H.; Umhoefer, P. J.; Oskin, M. E.; Dorsey, R. J.

    2013-12-01

    Tectonic reconstructions of the Pacific-North America (PAC-NAM) plate boundary across the Gulf of California and Salton Trough (GCAST) constrain the controversial magnitude of Baja California microplate-North America (BCM-NAM) relative motion since middle Miocene time. We use estimates of total PAC-NAM relative dextral-oblique motion from the updated global plate-circuit model (Atwater and Stock, 2013; GSA Cordilleran Mtg) to resolve the proportion of this motion on faults east of the BCM. Modern GPS studies and offset of late Miocene cross-gulf geologic tie points both suggest that BCM has never been completely coupled to the Pacific plate. Thus, our preferred GCAST reconstruction uses 93% BCM-PAC coupling from the present back to 6 Ma. We assume BCM-PAC coupling of 60% between 6 and 7 Ma, and 25% between 7 and 11 Ma, to avoid unacceptable overlap of continental crustal blocks between Baja California and the Sierra Madre Occidental (on stable NAM). Using these coupling ratios and PAC-NAM stage Euler poles, we determine the azimuth and velocity of individual points on the BCM in 1 million year increments back to 11 Ma. This procedure accounts for minor clockwise rotation of BCM that occurred during oblique rifting, and shows how total BCM-NAM relative motion increases from north to south due to greater distance from the Euler pole. Finer-scale restoration of tectonic blocks along significant (>1 km offset) faults, across extensional (e.g. pull-apart and half-graben) basins, and by vertical-axis rotation is constrained by local geologic and marine-geophysical datasets and accomplished via the open-source Tectonic Reconstruct ArcGIS tool. We find that restoration across the Gulf of California completely closes marine basins and their terrestrial predecessors between 6 and 9 Ma. Latest Miocene opening of these basins was coincident with a ~10° clockwise azimuthal change from 8 to 6 Ma in PAC-NAM relative motion, as revealed by the global plate circuit model. The

  13. A Globally Self-Consistent Model of Plate Motions Relative to the Hotspots for the Past 48 Million Years

    NASA Astrophysics Data System (ADS)

    Koivisto, E.; Gordon, R. G.

    2012-04-01

    Hotspots are volcanic anomalies, either in an intraplate setting or in the form of excessive volcanism along the plate boundaries, not explained by classic plate tectonics. In the early 70's, along with a deep mantle origin, hotspots were proposed to move so slowly relative to one another such that they could be used as a reference frame fixed in the deep mantle for describing plate motions in an "absolute" sense. Ever since the idea was first introduced, however, the rates of relative hotspot motion, and thus the limits of the hotspot frame of reference, have remained a source of heated debate with suggestions ranging from apparent fixity to rapid motion between the hotspots. The question of inter-hotspot motion is closely related to the estimation of true polar wander—rotation of the whole solid earth relative to the spin axis. A fundamental problem of global tectonics and paleomagnetism is determining which part of apparent polar wander—the apparent movement of age-progressive paleomagnetic poles relative to the continent in question—is due to plate motion, and which part is due to true polar wander. One approach for separating these is available if the hotspots are indeed tracking the motion of the mantle beneath the asthenosphere and are moving slowly relative to one another. In this case, a model of plate motion relative to the hotspots can be used to predict the positions of past paleomagnetic poles relative to the spin axis and thus estimate the amount of true polar wander. Cumulative improvements in the age progression along the hotspot tracks, the geomagnetic reversal time scale, and relative plate reconstructions lead to significant changes in earlier results. In this study, we build on a new method for objectively estimating plate-hotspot rotations and their uncertainties, and on our recent results that have demonstrated no significant motion between the Pacific and Indo-Atlantic hotspots since 48 Ma, and present a globally self-consistent model

  14. Mechanisms of Family Impact on African American Adolescents’ HIV-Related Behavior

    PubMed Central

    Kogan, Steven M.; Brody, Gene H.; Gibbons, Frederick X.; Chen, Yi-fu; Grange, Christina M.; Simons, Ronald L.; Gerrard, Meg; Cutrona, Carolyn E.

    2010-01-01

    A longitudinal model that tested mediating pathways between protective family processes and HIV-related behavior was evaluated with 195 African American youth. Three waves of data were collected when the youth were 13, 15, and 19 years old. Evidence of mediation and temporal priority were assessed for three constructs: academic engagement, evaluations of prototypical risk-taking peers, and affiliations with risk-promoting peers. Structural equation modeling indicated that protective family processes assessed during early adolescence were associated with HIV-related behavior during emerging adulthood and that academic engagement, evaluations of prototypical risk-taking peers, and affiliations with risk-promoting peers accounted for this association. Evidence of a specific pathway emerged: protective family processes → academic engagement negative → evaluations of prototypical risk-taking peers→ affiliations with risk-promoting peers→ HIV-related behavior. Academic engagement also was a direct predictor of HIV-related risk behavior. PMID:21643492

  15. Development of Obesity and Related Diseases in African Refugees After Resettlement to United States.

    PubMed

    Rhodes, Corinne M; Chang, Yuchiao; Percac-Lima, Sanja

    2016-12-01

    Despite increases in obesity and related diseases in developing nations, initial refugee clinical visits do not address these issues. We explored the development of obesity and related diseases in a longitudinal prospective cohort of African refugees resettling in northeastern US. Using state Department of Health data, refugees were linked to a health system. Body mass index, diabetes, hypertension, and hyperlipidemia status were extracted from charts. US regional controls from NAMCS/NHAMCS data were matched by age, sex, race, and visit year. African refugee BMI increased after resettlement at 1 (1.7 ± 2.9, p < 0.0001) and 5 years (3.1 ± 3.7, p < 0.0001), a different trend than matched regional controls (p = 0.01). Refugees had increased rates of diabetes (1.0 vs. 10.8 %, p < 0.0001), hypertension (16.7 vs. 21.6 %, p < 0.0001) and hyperlipidemia (3.9 vs. 10.8 %, p < 0.0001) at 5 years not observed in regional controls. Our findings emphasize the need for interventions during resettlement to prevent development of obesity and related disease in this vulnerable population.

  16. High lipid order of Arabidopsis cell-plate membranes mediated by sterol and DYNAMIN-RELATED PROTEIN1A function.

    PubMed

    Frescatada-Rosa, Márcia; Stanislas, Thomas; Backues, Steven K; Reichardt, Ilka; Men, Shuzhen; Boutté, Yohann; Jürgens, Gerd; Moritz, Thomas; Bednarek, Sebastian Y; Grebe, Markus

    2014-12-01

    Membranes of eukaryotic cells contain high lipid-order sterol-rich domains that are thought to mediate temporal and spatial organization of cellular processes. Sterols are crucial for execution of cytokinesis, the last stage of cell division, in diverse eukaryotes. The cell plate of higher-plant cells is the membrane structure that separates daughter cells during somatic cytokinesis. Cell-plate formation in Arabidopsis relies on sterol- and DYNAMIN-RELATED PROTEIN1A (DRP1A)-dependent endocytosis. However, functional relationships between lipid membrane order or lipid packing and endocytic machinery components during eukaryotic cytokinesis have not been elucidated. Using ratiometric live imaging of lipid order-sensitive fluorescent probes, we show that the cell plate of Arabidopsis thaliana represents a dynamic, high lipid-order membrane domain. The cell-plate lipid order was found to be sensitive to pharmacological and genetic alterations of sterol composition. Sterols co-localize with DRP1A at the cell plate, and DRP1A accumulates in detergent-resistant membrane fractions. Modifications of sterol concentration or composition reduce cell-plate membrane order and affect DRP1A localization. Strikingly, DRP1A function itself is essential for high lipid order at the cell plate. Our findings provide evidence that the cell plate represents a high lipid-order domain, and pave the way to explore potential feedback between lipid order and function of dynamin-related proteins during cytokinesis.

  17. Temperature dependence of Eu-related EPR spectra in CsBr:Eu needle image plates

    SciTech Connect

    Loncke, F.; Vrielinck, H.; Matthys, P.; Callens, F.; Tahon, J.-P.; Leblans, P.; Ahmad, I.; Goovaerts, E.

    2009-05-01

    Vacuum-deposited CsBr needle plates doped with Eu{sup 2+} have been investigated with Q ({approx}34 GHz) and W ({approx}95 GHz) band electron paramagnetic resonance in a large temperature interval (4 K: room temperature). At low temperatures (<35 K), two Eu-related centers were found with different symmetry (tetragonal and orthorhombic), while in earlier studies at room temperature only one center was found with tetragonal symmetry. Possible models for the three defects are investigated, taking into account their temperature behavior, their symmetry, and the atypical values of their zero-field splitting parameters.

  18. Orthogonal relation of elastic modes in two-layered plate with weak interface

    NASA Astrophysics Data System (ADS)

    Du, Jun; Cheng, Jianchun

    2002-05-01

    The orthogonal features of the guided wave-modes have been discussed in details for a two-layered plate with a weak interface. The elastic operator is proved to be a self-adjoint operator under the weak interface modeled by the spring model. However, it is proved to be non-self-adjoint operator, and a new orthogonal relation is derived for the weak interface modeled by the density model. The theoretical analyses are verified by numerical calculations for the spring model.

  19. Seismicity of the diffusive Iberian/African plate boundary at the eastern terminus of the Azores-Gibraltar Transform fault

    NASA Astrophysics Data System (ADS)

    Lange, D.; Grevemeyer, I.; Matias, L. M.

    2014-12-01

    The plate boundary at the eastern terminus of the Azores-Gibraltar transform fault between Africa and Iberia is poorly defined. The deformation in the area is forced by the slow NW-SE convergence of 4 mm/yr between the oceanic domains of Iberia/Eurasia and Africa and is accommodated over a 200 km broad tectonically-active deformation zone. The region, however, is also characterized by large earthquakes, such as the 1969 Mw=7.9 Horseshoe event and the November 1, 1755 Great Lisbon earthquake with an estimated magnitude of Mw~8.5. The exact location of the source of the 1755 Lisbon earthquake is still unknown. Recent work may suggest that the event occurred in the vicinity of the Horseshoe fault, an oblique thrust fault. However, estimates of tsunami arrival times suggested a source near the Gorringe Bank, a ~180 km-long and ~70 km-wide ridge that has a relieve of ~5000 m. Deep Sea Drilling (DSDP) and rock samples indicated that the bank is mainly composed of serpentinized peridotites with gabbroic intrusions, perhaps being created by overthrusting of the Horseshoe Abyssal Plain onto the Tagus Abyssal Plain in NW direction. Further, the Horseshoe Abyssal Plain is marked by the presence of compressive structures with a roughly NE-SW orientation and E-W trending, segmented, crustal-scale, strike slip faults that extend from the Gorringe Bank to the Gibraltar Arc in the eastern Gulf of Cadiz, which were called "South West Iberian Margin" or SWIM faults. The fault system may mark a developing Eurasia-Africa plate boundary. Two local seismic networks were operated in the area. First, a network of 14 ocean-bottom seismometers (OBS) was operated between April and October 2012 in the vicinity of the Horseshoe fault between 10°W to 11°W, and 35°50'N to 36°10'N. From October 2013 to March 2014 a second network of 15 OBS monitored seismicity at the Gorringe Bank. Both networks benefitted from seismic stations operated in Portugal. The first network provided in the order of

  20. Seismicity and seismotectonics of the diffusive Iberian/African plate boundary: Horseshoe Abyssal Plain and Gorringe Bank

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Lange, Dietrich; Matias, Luis

    2014-05-01

    In the area to the west of the Gibraltar Arc the plate boundary between Africa and Iberia is poorly defined. The deformation in the area is forced by the slow NW-SE convergence of 4 mm/yr between the oceanic domains of Iberia/Eurasia and Africa and is accommodated over a 200 km broad tectonically-active deformation zone. The region, however, is also characterized by large earthquakes and tsunamis, such as the 1969 Mw=7.9 Horseshoe Abyssal Plain earthquake and the November 1, 1755 Great Lisbon earthquake with an estimated magnitude of Mw~8.5. The exact location of the source of the 1755 Lisbon earthquake is still unknown. Recent work may suggest that the event occurred in the vicinity of the Horseshoe fault, an oblique thrust fault. However, estimates of tsunami arrival times suggested a source near the Gorringe Bank, a ~180 km-long and ~70 km-wide ridge that has a relieve of ~5000 m. Deep Sea Drilling (DSDP) and rock samples indicated that the bank is mainly composed of serpentinized peridotites with gabbroic intrusions, perhaps being created by overthrusting of the Horseshoe Abyssal Plain onto the Tagus Abyssal Plain in NW direction. Further, the Horseshoe Abyssal Plain is marked by the presence of compressive structures with a roughly NE-SW orientation and E-W trending, segmented, crustal-scale, strike slip faults that extend from the Gorringe Bank to the Gibraltar Arc in the eastern Gulf of Cadiz, which were called "South West Iberian Margin" or SWIM faults. The fault system may mark a developing Eurasia-Africa plate boundary. Two local seismic networks were operated in the area. First, a network of 14 ocean-bottom seismometers (OBS) was operated between April and October 2012 in the vicinity of the Horseshoe fault between 10°W to 11°W, and 35°50'N to 36°10'N. From October 2013 to March 2014 a second network of 15 OBS monitored seismicity at the Gorringe Bank. Both networks benefitted from seismic stations operated in Portugal. The first network provided in

  1. Basin filling related to the Philippine Sea Plate motion in Beppu Bay, southwest Japan

    NASA Astrophysics Data System (ADS)

    Yamada, Keitaro; Takemura, Keiji; Kuwae, Michinobu; Ikehara, Ken; Yamamoto, Masanobu

    2016-03-01

    Strike-slip basins are one of the most important accumulation spaces for sediment of terrigenous, biogenic, and volcanic origins, and generally include large amount of event deposits. Although these event deposits are important basin filling process, research on this topic, particularly the effects of event deposits, is insufficient. In this study, we discuss sedimentation features based on grain composition and other properties for ca. 3000 year periods in Beppu Bay, which is strike-slip basin located at the western end of an arc-bisecting dextral fault known as Median Tectonic Line (MTL) associated with the northwestward subduction of the Philippine Sea Plate. This sediment is composed of hemipelagic clay and coarser event layers of turbidites referred to as types A, B, and C; ash layers referred to as type D; and other referred to as type E. The turbidite event layers, which accounted for 92% of the total major event layer, with >1 cm thickness, consist of particles related to volcanism, including hydrothermal activity. The events control the regional filling rate and transportation of coarse and heavy volcaniclastic materials. In particular, type A, which accounted for 73% of the total major event layer thickness, is likely induced by earthquakes related to the MTL, according to its age. As a result, the basin filling processes are controlled mainly by tectonics related to the subduction of the Philippine Sea Plate.

  2. Blood pressure, prevalence of hypertension and hypertension related complications in Nigerian Africans: A review

    PubMed Central

    Ogah, Okechukwu S; Okpechi, Ikechi; Chukwuonye, Innocent I; Akinyemi, Joshua O; Onwubere, Basden JC; Falase, Ayodele O; Stewart, Simon; Sliwa, Karen

    2012-01-01

    To review studies on hypertension in Nigeria over the past five decades in terms of prevalence, awareness and treatment and complications. Following our search on Pubmed, African Journals Online and the World Health Organization Global cardiovascular infobase, 1060 related references were identified out of which 43 were found to be relevant for this review. The overall prevalence of hypertension in Nigeria ranges from 8%-46.4% depending on the study target population, type of measurement and cut-off value used for defining hypertension. The prevalence is similar in men and women (7.9%-50.2% vs 3.5%-68.8%, respectively) and in the urban (8.1%-42.0%) and rural setting (13.5%-46.4%).The pooled prevalence increased from 8.6% from the only study during the period from 1970-1979 to 22.5% (2000-2011). Awareness, treatment and control of hypertension were generally low with attendant high burden of hypertension related complications. In order to improve outcomes of cardiovascular disease in Africans, public health education to improve awareness of hypertension is required. Further epidemiological studies on hypertension are required to adequately understand and characterize the impact of hypertension in society. PMID:23272273

  3. Sex-Related Alcohol Expectancies among African American Women Attending an Urban STI Clinic

    PubMed Central

    Hutton, Heidi E.; McCaul, Mary E.; Norris, Jeanette; Valliant, Julia D.; Abrefa-Gyan, Tina; Chander, Geetanjali

    2014-01-01

    African American women are disproportionately affected by HIV/AIDS and sexually transmitted infections (STIs). Alcohol use is a significant risk factor for HIV/STI acquisition. Sex related alcohol expectancies (SRAE) may partially account for alcohol related risky sexual behaviors. Using qualitative interviews we explored the link between alcohol use and risky sex among 20 African American women attending an STI clinic who had consumed ≥4 alcoholic drinks per drinking day (binge drinking) and/or reported vaginal or anal sex while under the influence of alcohol. Four SRAE emerged which we named: drink for sexual desire, drink for sexual power, drink for sexual excuse, and drink for anal sex. While the desire SRAE has been documented, this study identified three additional SRAEs not currently assessed by expectancy questionnaires. These SRAEs may contribute to high-risk sex when under the influence of alcohol, and suggests the importance of developing integrated alcohol-sexual risk reduction interventions for high-risk women. PMID:25110958

  4. Predictors of HIV-related stigmas among African American and Latino religious congregants

    PubMed Central

    Derose, Kathryn Pitkin; Kanouse, David E.; Bogart, Laura M.; Griffin, Beth Ann; Haas, Ann; Stucky, Brian D.; Williams, Malcolm V.; Flórez, Karen R.

    2015-01-01

    Objectives Inform church-based stigma interventions by exploring dimensions of HIV stigma among African American and Latino religious congregants and how these are related to drug addiction and homosexuality stigmas and knowing someone HIV-positive. Methods In-person, self-administered surveys of congregants 18+ years old across two African American and three Latino churches (n=1235, response rate 73%) in a western US city with high HIV prevalence. Measures included 12 items that captured dimensions of HIV stigma, a 5-item scale that assessed attitudes towards people who are addicted to drugs, a 7-item scale assessing attitudes towards homosexuality, and questions regarding socio-demographics and previous communication about HIV. Results 63.8% of survey participants were women, mean age was 40.2 years, and 34.4% were African American, 16.8% were U.S.-born Latinos, 16.0% were foreign-born, English-speaking Latinos, and 32.9% were foreign-born, Spanish-speaking Latinos. Exploratory and confirmatory factor analyses identified four dimensions of HIV stigma – discomfort interacting with people with HIV (4 items, α=0.86), feelings of shame “if you had HIV” (3 items, α=0.78), fears of rejection “if you had HIV” (3 items, α=0.71) and feelings of blame towards people with HIV (2 items, α=0.65). Across all dimensions, after controlling for socio-demographic characteristics and previous communication about HIV, knowing someone with HIV was associated with lower HIV stigma, and greater stigma concerning drug addiction and homosexuality were associated with higher HIV stigma. Conclusions Congregation-based HIV stigma reduction interventions should consider incorporating contact with HIV-affected people. It may also be helpful to address attitudes toward drug addiction and sexual orientation. PMID:26213890

  5. The 2011 Tohoku-oki Earthquake related to a large velocity gradient within the Pacific plate

    NASA Astrophysics Data System (ADS)

    Matsubara, Makoto; Obara, Kazushige

    2015-04-01

    rays from the hypocenter around the coseismic region of the Tohoku-oki earthquake take off downward and pass through the Pacific plate. The landward low-V zone with a large anomaly corresponds to the western edge of the coseismic slip zone of the 2011 Tohoku-oki earthquake. The initial break point (hypocenter) is associated with the edge of a slightly low-V and low-Vp/Vs zone corresponding to the boundary of the low- and high-V zone. The trenchward low-V and low-Vp/Vs zone extending southwestward from the hypocenter may indicate the existence of a subducted seamount. The high-V zone and low-Vp/Vs zone might have accumulated the strain and resulted in the huge coseismic slip zone of the 2011 Tohoku earthquake. The low-V and low-Vp/Vs zone is a slight fluctuation within the high-V zone and might have acted as the initial break point of the 2011 Tohoku earthquake. Reference Matsubara, M. and K. Obara (2011) The 2011 Off the Pacific Coast of Tohoku earthquake related to a strong velocity gradient with the Pacific plate, Earth Planets Space, 63, 663-667. Okada, Y., K. Kasahara, S. Hori, K. Obara, S. Sekiguchi, H. Fujiwara, and A. Yamamoto (2004) Recent progress of seismic observation networks in Japan-Hi-net, F-net, K-NET and KiK-net, Research News Earth Planets Space, 56, xv-xxviii.

  6. Oceanic Remnants In The Caribbean Plate: Origin And Loss Of Related LIPs.

    NASA Astrophysics Data System (ADS)

    Giunta, G.

    2005-12-01

    The modern Caribbean Plate is an independent lithospheric entity, occupying more than 4 Mkm2 and consisting of the remnants of little deformed Cretaceous oceanic plateau of the Colombia and Venezuela Basins (almost 1 Mkm2) and the Palaeozoic-Mesozoic Chortis continental block (about 700,000 km2), both bounded by deformed marginal belts. The northern (Guatemala and Greater Antilles) and the southern (northern Venezuela) plate margins are marked by collisional zones, whereas the western (Central America Isthmus) and the eastern (Lesser Antilles) margins are represented by convergent boundaries and their magmatic arcs, all involving ophiolitic terranes. The evolutionary history of the Caribbean Plate since the Jurassic-Early Cretaceous encompasses plume, accretionary, and collisional tectonics, the evidence of which has been recorded in the oceanic remnants of lost LIPs, as revealed in: i) the MORB to OIB thickened crust of the oceanic plateau, including its un-deformed or little deformed main portion, and scattered deformed tectonic units; ii) ophiolitic tectonic units of MORB affinity and the rock blocks in ophiolitic melanges; iii) intra-oceanic, supra subduction magmatic sequences with IAT and CA affinities. The Mesozoic oceanic LIPs, from which the remnants of the Caribbean Plate have been derived, have been poorly preserved during various episodes of the intra-oceanic convergence, either those related to the original proto-Caribbean oceanic realm or those connected with two eo-Caribbean stages of subduction. The trapped oceanic plateau of the Colombia and Venezuela Basins is likely to be an unknown portion of a bigger crustal element of a LIP, similar to the Ontong-Java plateau. The Jurassic-Early Cretaceous proto-Caribbean oceanic domain consists of oceanic crust generated at multiple spreading centres; during the Cretaceous, part of this crust was thickened to form an oceanic plateau with MORB and OIB affinities. At the same time, both South and North American

  7. The proportionality between relative plate velocity and seismicity in subduction zones

    NASA Astrophysics Data System (ADS)

    Ide, Satoshi

    2013-09-01

    Maximum earthquake magnitude and the rate of seismic activity apparently differ among subduction zones. This variation is attributed to factors such as subduction zone temperature and stress, and the type of material being subducted. The relative velocity between the downgoing and overriding plates controls their tectonic deformation. It is also thought to correlate with seismicity. Here I use the epidemic type aftershock sequence model to calculate the background seismicity rate--the frequency of seismic events above magnitude 4.5--for 117 sections of subduction zones worldwide, during the past century. I demonstrate a proportionality relationship whereby relative plate velocity correlates positively with seismicity rate. This relationship is prominent in the southwestern Pacific Ocean. However, although seismically active, this region has not experienced a magnitude 9 earthquake since 1900. In contrast, the Cascadia, Nankai, southern Chilean and Alaskan subduction zones exhibit low background seismicity rates, yet have experienced magnitude 9 earthquakes in the past century. Slow slip occurs in many of these regions, implying that slow deformation may aid nucleation of very large earthquakes. The proportionality relationship could be used to assess the seismic risk between two endmembers: active subduction zones that generate moderate earthquakes and quiet subduction zones that generate extremely large earthquakes.

  8. Poor relation between biomechanical and clinical studies for the proximal femoral locking compression plate.

    PubMed

    Viberg, Bjarke; Rasmussen, Katrine M V; Overgaard, Søren; Rogmark, Cecilia

    2017-03-13

    Background and purpose - The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between biomechanical and clinical studies on PF-LCP. Methods - A systematic literature search of relevant biomechanical and clinical studies was conducted in PubMed on December 1, 2015. 7 biomechanical studies and 15 clinical studies were included. Results - Even though the biomechanical studies showed equivalent or higher failure loads for femoral neck fracture, the clinical results were far worse, with a 37% complication rate. There were no biomechanical studies on pertrochanteric fractures. Biomechanical studies on subtrochanteric fractures showed that PF-LCP had a lower failure load than with proximal femoral nail, but higher than with angled blade plate. 4 clinical studies had complication rates less than 8% and 9 studies had complication rates between 15% and 53%. Interpretation - There was no clear relation between biomechanical and clinical studies. Biomechanical studies are generally inherently different from clinical studies, as they examine the best possible theoretical use of the implant without considering the long-term outcome in a clinical setting. Properly designed clinical studies are mandatory when introducing new implants, and they cannot be replaced by biomechanical studies.

  9. Plate tectonics of the Red Sea and East Africa.

    PubMed

    McKenzie, D P; Davies, D; Molnar, P

    1970-04-18

    The relative motion between the plates on each side of the East African Rift Valley can be obtained from the opening of the Red Sea and the Gulf of Aden. The calculated direction of relative motion agrees well with fault plane solutions for earthquakes north of the equator.

  10. Seasonal variation in the relative dominance of herbivore guilds in an African savanna.

    PubMed

    Davies, Andrew B; van Rensburg, Berndt J; Robertson, Mark P; Levick, Shaun R; Asner, Gregory P; Parr, Catherine L

    2016-06-01

    African savannas are highly seasonal with a diverse array of both mammalian and invertebrate herbivores, yet herbivory studies have focused almost exclusively on mammals. We conducted a 2-yr exclosure experiment in South Africa's Kruger National Park to measure the relative impact of these two groups of herbivores on grass removal at both highly productive patches (termite mounds) and in the less productive savanna matrix. Invertebrate and mammalian herbivory was greater on termite mounds, but the relative importance of each group changed over time. Mammalian offtake was higher than invertebrates in the dry season, but can be eclipsed by invertebrates during the wet season when this group is more active. Our results demonstrate that invertebrates play a substantial role in savanna herbivory and should not be disregarded in attempts to understand the impacts of herbivory on ecosystems.

  11. Theory-guided intervention for preventing diabetes-related amputations in African Americans.

    PubMed

    Scollan-Koliopoulos, Melissa

    2004-12-01

    A disproportionate number of individuals of African American descent undergo lower extremity amputations because of complications from diabetes mellitus (American Diabetes Association 2001). It is estimated that up to 85% of lower extremity amputations can be prevented through programs for preventing and treating foot ulcers, preventing reoccurrence of ulcers, and educating patients about proper foot care (American Diabetes Association 2001). The primary purpose of this article is to describe a church-based educational intervention that was developed to assist individuals of African American descent in the prevention of lower extremity amputations resulting from diabetes. The intervention was designed with the Health Belief Model as the framework. The secondary purpose of this article is to demonstrate the feasibility of using the Roy Adaptation Model as a framework for the same intervention. A comparison of the two frameworks is intended to support the use of the Roy Adaptation Model as a useful guide in the development of community-based nursing interventions. The current nursing literature (based on a search in CINHAL 1995-2003 and MEDLINE 1995-2003) exhibits an abundance of use of health behavior theories not authored by nurses that are used to guide interventions. The comparison of a health promotion model such as the Health Belief Model and a nursing theory is essential to address the relative lack of presence of the use of nursing theories in the realm of health-promoting interventions by nurses.

  12. African penguins (Spheniscus demersus) can detect dimethyl sulphide, a prey-related odour.

    PubMed

    Cunningham, Gregory B; Strauss, Venessa; Ryan, Peter G

    2008-10-01

    Although it is well established that certain procellariiform seabirds use odour cues to find prey, it is not clear whether penguins use olfactory cues to forage. It is commonly assumed that penguins lack a sense of smell, yet they are closely related to procellariiforms and forage on similar types of prey in similar areas to many procellariiforms. Such regions are characterized by having high levels of dimethyl sulphide (DMS) a scented compound that many marine animals use to locate foraging grounds. If penguins can smell, DMS may be a biologically relevant scented compound that they may be sensitive to in nature. To test this hypothesis, we investigated whether adult African penguins (Spheniscus demersus) could detect DMS using two separate experiments. We tested wild penguins on Robben Island, South Africa, by deploying mumolar DMS solutions in the colonies, and found that birds slowed down their walking speeds. We also tested captive penguins in a Y-maze. In both cases, our data convincingly demonstrate that African penguins have a functioning sense of smell and are attracted to DMS. The implication of this work is that the detection of changes in the odour landscape (DMS) may assist penguins in identifying productive areas of the ocean for foraging. At-sea studies are needed to investigate this issue further.

  13. South African women's conceptualisations of and responses to sexual coercion in relation to hegemonic masculinities.

    PubMed

    Stern, Erin; Buikema, Rosemarie; Cooper, Diane

    2016-01-01

    Despite the documented relationship between hegemonic norms of masculinities and South African men's use of sexual violence, less is known about how women's engagement with norms of masculinity influences their agency in sexually coercive experiences. This study applied a narrative approach to assess how women's understandings of hegemonic male norms affected their perceptions of and responses to sexually coercive experiences. Twenty-five sexual history narrative interviews were conducted with women across five South African provinces representing a range of ages, language and sociocultural backgrounds. Interviews elicited stories of first experiences of sex and the range of sexual relationships through adulthood. Data were analysed using principles of thematic and narrative analysis. Coercive sexual experiences informed many women's normative ideas about men's sexuality including being impulsive, controlling and aggressive. This could underpin women's limited ability to exercise agency and their increased vulnerability to sexual abuse. Some women reported levels of trust and respect in subsequent relationships, which typically involved deconstructing norms of men's use of coercion and moving beyond self-blame and guilt. The findings highlight the need to appreciate the fluid and situated nature of women's agency from a relational perspective in terms of how women condone and challenge gender norms that support men's use of sexual violence in their relationships.

  14. Making sense of abstinence: social representations in young Africans' HIV-related narratives from six countries.

    PubMed

    Winskell, Kate; Beres, Laura K; Hill, Elizabeth; Mbakwem, Benjamin Chigozie; Obyerodhyambo, Oby

    2011-09-01

    Despite the prominence of abstinence promotion in HIV prevention for young Africans, there is little documentation concerning its reception and interpretation. With the purpose of informing programmatic practice, we examined how young Africans from six countries with contrasting HIV prevalence rates make sense of abstinence. 'Scenarios from Africa' scriptwriting contests invite young people to contribute ideas for short films about HIV. Using thematic narrative-based approaches, we analyzed a stratified random sample of these narratives written in 2005 by young women and men aged 10-24 years from Senegal, Burkina Faso, South-East Nigeria, Kenya, Namibia and Swaziland. Abstinence was considerably more prominent as a theme in the samples from SE Nigeria, Kenya and Swaziland. It was articulated in relation to conservative Christian sexual morality and in opposition to condom use with particular intensity in SE Nigeria, with stigmatising implications for non-abstainers. However, cross-national commonalities were more striking than differences. Examples of non-stigmatising pro-abstinence messaging highlighted the appeal of discourses of romantic love and future plans across countries and demographic characteristics. The analysis yielded contextual understanding, youth-driven ideas and recommendations to inform comprehensive HIV-prevention efforts.

  15. Post-Pan-African tectonic evolution of South Malawi in relation to the Karroo and recent East African rift systems

    NASA Astrophysics Data System (ADS)

    Castaing, C.

    1991-05-01

    Structural studies conducted in the Lengwe and Mwabvi Karroo basins and in the basement in South Malawi, using regional maps and published data extended to cover Southeast Africa, serve to propose a series of geodynamic reconstructions which reveal the persistence of an extensional tectonic regime, the minimum stress σ3 of which has varied through time. The period of Karroo rifting and the tholeiitic and alkaline magmatism which terminated it, were controlled by NW-SE extension, which resulted in the creation of roughly NE-SW troughs articulated by the Tanganyika-Malawi and Zambesi pre-transform systems. These were NW-SE sinistral-slip systems with directions of movement dipping slightly to the Southeast, which enabled the Mwanza fault to play an important role in the evolution of the Karroo basins of the Shire Valley. The Cretaceous was a transition period between the Karroo rifting and the formation of the Recent East African Rift System. Extension was NE-SW, with some evidence for a local compressional episode in the Lengwe basin. Beginning in the Cenozoic, the extension once more became NW-SE and controlled the evolution in transtension of the Recent East African Rift System. This history highlights the major role of transverse faults systems dominated by strike-slip motion in the evolution and perpetuation of the continental rift systems. These faults are of a greater geological persistence than the normal faults bounding the grabens, especially when they are located on major basement anisotropies.

  16. Past Plate Motions and The Evolution of Earth's Lower Mantle: Relating LLSVPs and Plume Distribution

    NASA Astrophysics Data System (ADS)

    Bull, A. L.; Torsvik, T. H.; Shephard, G. E.

    2015-12-01

    Seismic tomography elucidates broad, low shear-wave velocity structures in the lower mantle beneath Africa and the central Pacific with uncertain physical and compositional origins. The anomalously slow areas, which cover nearly 50% of the core-mantle boundary, are often referred to as Large Low Shear Velocity Provinces (LLSVPs) due to the reduced velocity of seismic waves passing through them. Several hypotheses have arisen to explain the LLSVPs in the context of large-scale mantle convection. One end-member scenario infers a spatial correlation between LLSVP margins at depth and the reconstructed surface eruption sites of hotspots, kimberlites, and Large Igneous Provinces. Such a correlation has been explained by the preferential triggering of plumes at LLSVP margins by impingement of the subducting lithosphere upon the lower thermal boundary layer at the interface between ambient mantle and the higher density structures. This scenario propounds that Earth's plate motion history plays a controlling role in plume development, and that the location, geometry and morphology of plumes may be influenced by the movement of subducting slabs. Here, we investigate what is necessary to create such a pattern of plume distribution in relation to LLSVPs. We consider what effect past plate motions may have had on the evolution of Earth's lower mantle, and discuss the development of mantle plumes in terms of subduction dynamics. We integrate plate tectonic histories and numerical models of mantle convection to investigate the role that subduction history plays in the development and evolution of plumes in the presence of LLSVPs. To test whether an interaction exists between the surface location of subduction and plume eruption sites, and if so, to what degree over time, we apply varying shifts to the absolute reference frame of the plate reconstruction. With this method, we are able to change the location of subduction at the surface and thus the global flow field. This in turn

  17. Cretaceous Pacific plate movement beneath SE China: Evidence from episodic volcanism and related intrusions

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Xu, Xisheng; Xia, Yan

    2014-02-01

    Extensive Late Mesozoic igneous rocks in SE China have been widely considered to be generated under the paleo-Pacific tectonic regime, the plate subduction model, however, remains controversial. This study focuses on the Cretaceous volcanic rocks in northwestern Zhejiang Province. Zircon U-Pb age determination indicates that Cretaceous volcanism in northwestern Zhejiang took place at three episodes of 140-130, 130-127 and 123-118 Ma, in good agreement with the coeval lower volcanic series in southeastern Zhejiang, but lacking the episode at 110-88 Ma corresponding to the upper volcanic series. The Cretaceous volcanic rocks in Zhejiang therefore show an oceanward younging trend. In situ zircon Hf isotope analyses of three episodes of volcanics yield ɛHf(t) values of - 11.2 to - 8.7, -4.8 to - 2.4 and - 4.4 to + 2.2, respectively. The entire sequences display typical isotopic features of magma mixing, implying progressive involvement of juvenile component. Based on systematical researches on the Cretaceous volcanic rocks and a series of granitoid plutons in Zhejiang, it is also identified that the juvenile component involvement gradually occurred from the inland to the coast under an enhanced lithospheric extensional tectonic setting. All the observations in this study indicate the northwestward paleo-Pacific plate subduction with episodic slab rollback which triggered the arc system to retreat towards the Pacific Ocean, rather than the southwestward subduction related to the ridge subduction along the Lower Yangtze River belt.

  18. Associations between depression, distress tolerance, delay discounting, and alcohol-related problems in European American and African American college students.

    PubMed

    Dennhardt, Ashley A; Murphy, James G

    2011-12-01

    Although levels of heavy drinking and alcohol-related problems are high in college students, there is significant variability in the number and type of problems experienced, even among students who drink heavily. African American students drink less and experience fewer alcohol-related problems than European American students, but are still at risk, and little research has investigated the potentially unique patterns and predictors of problems among these students. Depression, distress tolerance, and delay discounting have been implicated in adult substance abuse and may be important predictors of alcohol problem severity among college students. We examined the relationship between these variables and alcohol-related problems among African American and European American students (N = 206; 53% female; 68% European American; 28% African American) who reported recent heavy drinking. In regression models that controlled for drinking level, depression, distress tolerance, and delay discounting were associated with alcohol problems among African American students, but only depression was associated with alcohol problems among European American students. These results suggest that negative affect is a key risk factor for alcohol problems among college student drinkers. For African American students, the inability to tolerate negative emotions and to organize their behavior around future outcomes may also be especially relevant risk factors.

  19. Brief Report: The Number of Sexual Partners and Race-Related Stress in African American Adolescents--Preliminary Findings

    ERIC Educational Resources Information Center

    Stevens-Watkins, Danelle; Brown-Wright, Lynda; Tyler, Kenneth

    2011-01-01

    The current study examined the association between the number of lifetime sexual partners and race-related stress among African American 201 high school juniors and seniors at two urban high schools in the Southeastern region of the country. Students completed the Index of Race-Related Stress-Brief (IRRS-B) and the Youth Risk Behavior Survey…

  20. "No Matter What I Do They Still Want Their Family": Stressors for African American Grandparents and Other Relatives

    ERIC Educational Resources Information Center

    Linsk, Nathan; Mason, Sally; Fendrich, Michael; Bass, Michael; Prubhughate, Priti; Brown, Allene

    2009-01-01

    Grandparents and other relatives increasingly assume the role of primary caregiver to minor children. This study interviewed family members caring for children whose parents were not available due to parental incarceration, other involvement in the criminal justice system, and substance abuse-related issues. Interviews with 25 African American…

  1. Perceived Factors that Influence Career Decision Self-Efficacy and Engineering Related Goal Intentions of African American High School Students

    ERIC Educational Resources Information Center

    Austin, Chandra Yvette

    2010-01-01

    This study examined the relationship between specific factors believed to influence career decision self-efficacy and math/science related goal intentions (proxy for engineering related goal intentions) among African American high school students. Minority students generally tend to be underrepresented in such careers, as indicated by the National…

  2. HIV-Related Sexual Risk Behavior Among African American Adolescent Girls

    PubMed Central

    Walsh, Kate; McCauley, Jenna; Ruggiero, Kenneth J.; Brown, Jennifer L.; Sales, Jessica M.; Rose, Eve; Wingood, Gina M.; DiClemente, Ralph J.

    2014-01-01

    Abstract Background: Latent class analysis (LCA) is a useful statistical tool that can be used to enhance understanding of how various patterns of combined sexual behavior risk factors may confer differential levels of HIV infection risk and to identify subtypes among African American adolescent girls. Methods: Data for this analysis is derived from baseline assessments completed prior to randomization in an HIV prevention trial. Participants were African American girls (n=701) aged 14–20 years presenting to sexual health clinics. Girls completed an audio computer-assisted self-interview, which assessed a range of variables regarding sexual history and current and past sexual behavior. Results: Two latent classes were identified with the probability statistics for the two groups in this model being 0.89 and 0.88, respectively. In the final multivariate model, class 1 (the “higher risk” group; n=331) was distinguished by a higher likelihood of >5 lifetime sexual partners, having sex while high on alcohol/drugs, less frequent condom use, and history of sexually transmitted diseases (STDs), when compared with class 2 (the “lower risk” group; n=370). The derived model correctly classified 85.3% of participants into the two groups and accounted for 71% of the variance in the latent HIV-related sexual behavior risk variable. The higher risk class also had worse scores on all hypothesized correlates (e.g., self-esteem, history of sexual assault or physical abuse) relative to the lower risk class. Conclusions: Sexual health clinics represent a unique point of access for HIV-related sexual risk behavior intervention delivery by capitalizing on contact with adolescent girls when they present for services. Four empirically supported risk factors differentiated higher versus lower HIV risk. Replication of these findings is warranted and may offer an empirical basis for parsimonious screening recommendations for girls presenting for sexual healthcare services. PMID

  3. Victimization Experiences, Substance Misuse and Mental Health Problems in Relation to Risk for Lethality among African-American and African-Caribbean Women

    PubMed Central

    Sabri, Bushra; Stockman, Jamila K.; Betrand, Desiree; Campbell, Doris W.; Callwood, Gloria B.; Campbell, Jacquelyn C.

    2013-01-01

    The purpose of this study was to investigate the association of intimate partner victimization experiences, mental health, and substance misuse problems with the risk for lethality among women of African descent. Data for this cross-sectional study were derived from a large case-control study examining the relationship between abuse status and health consequences. Women were recruited from primary care, prenatal or family planning clinics in Baltimore and the US Virgin Islands. Logistic regression was used to generate the study findings. Among 543 abused women, physical and psychological abuse by intimate partners, comorbid PTSD and depression symptoms, and PTSD-only problems significantly increased the likelihood of lethality risk. However victims’ substance misuse and depression-only problems were not associated with the risk for lethality. Additionally, PTSD symptoms mediated the relationship between severe victimization experiences and risk for lethality. Practitioners should pay attention to victimization experiences and mental health issues when developing treatment and safety plans. Policies to fund integrated services for African-American and African-Caribbean women with victimization and related mental health issues, and training of providers to identify at-risk women may help reduce the risk for lethality in intimate partner relationships. PMID:23929602

  4. Partner influences and gender-related factors associated with noncondom use among young adult African American women.

    PubMed

    Wingood, G M; DiClemente, R J

    1998-02-01

    We examined the partner influences and gender-related correlates of noncondom use among African American women. The prevalence of noncondom use was 45.3%. Women whose sexual partners were noncondom users were four times more likely to believe that asking their partner to use a condom implied he was unfaithful, three times as likely to have a partner who resisted using condoms, three times more likely to receive AFDC, twice as likely to be sexually nonassertive, three times more likely to believe that it was not difficult to find an "eligible" African American man, and three times as likely to have had one sexual partner. HIV prevention tailored towards African American women should address these partner influences and gender-related factors.

  5. Perceptions of South African Emerging Adult FET College Students on Sexual Practices in Relation to Religion.

    PubMed

    Moodley, Colleen Gail

    2016-10-11

    HIV and AIDS are rapidly spreading amongst the world's 15- to 24-year age group, particularly in sub-Saharan Africa. Despite vigorous government interventions and campaigns, 10 % of South African youth in the age cohort 15-24 are infected with HIV and AIDS. Furthermore, for the first time in history the world has its largest number of individuals under the age of 30 years. Researchers are desperately seeking a solution and have found religion to play an important role in moderating risky sexual behaviour amongst youth. This exploratory qualitative study aims to increase our understanding of emerging adult Further Education and Training (FET) students' perceptions of the role of religion and religious beliefs in their sexual decision-making and practices. The qualitative data emerged from five focus group discussions, each consisting of 12 heterosexual emerging adult FET college students aged 18-24 years, selected using random sampling. Participants were representative of all the major South African racial groups (Blacks, Whites, Coloured and Indians) as well as different religious and cultural groupings. Secularisation theory was used as a theoretical framework for this study. These focus group discussions revealed the following themes: Theme 1-religious institutions need to embrace change in order to become effective social agents of change. Theme 2-a need for open discussion and communication concerning current issues related to young people's sexual health (by religious institutions/religious leaders). Theme 3-perceptions of religion's negative sanctions towards sexual behaviour. Theme 4-religious leaders' indifference and abdication of responsibility to the problems that youth face. Theme 5-religion and condom-related beliefs. Theme 6-perceptions of religious leaders as role models. Theme 7-emerging adults general concern for the moral decay of society. Theme 8-perceptions of whether religion has an influence on young people's sexual decision-making and

  6. Hormone-Related Pathways and Risk of Breast Cancer Subtypes in African American Women

    PubMed Central

    Haddad, Stephen A.; Lunetta, Kathryn L.; Ruiz-Narváez, Edward A.; Bensen, Jeannette T.; Hong, Chi-Chen; Sucheston-Campbell, Lara E.; Yao, Song; Bandera, Elisa V.; Rosenberg, Lynn; Haiman, Christopher A.; Troester, Melissa A.; Ambrosone, Christine B.; Palmer, Julie R.

    2016-01-01

    Purpose We sought to investigate genetic variation in hormone pathways in relation to risk of overall and subtype-specific breast cancer in women of African ancestry (AA). Methods Genotyping and imputation yielded data on 143,934 SNPs in 308 hormone-related genes for 3663 breast cancer cases (1098 ER-, 1983 ER+, 582 ER unknown) and 4687 controls from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. AMBER includes data from four large studies of AA women: the Carolina Breast Cancer Study, the Women's Circle of Health Study, the Black Women's Health Study, and the Multiethnic Cohort Study. Pathway- and gene-based analyses were conducted, and single SNP tests were run for the top genes. Results There were no strong associations at the pathway level. The most significantly associated genes were GHRH, CALM2, CETP, and AKR1C1 for overall breast cancer (gene-based nominal p ≤0.01); NR0B1, IGF2R, CALM2, CYP1B1, and GRB2 for ER+ breast cancer (p ≤0.02); and PGR, MAPK3, MAP3K1, and LHCGR for ER- disease (p ≤0.02). Single-SNP tests for SNPs with pairwise linkage disequilibrium r2 <0.8 in the top genes identified 12 common SNPs (in CALM2, CETP, NR0B1, IGF2R, CYP1B1, PGR, MAPK3, and MAP3K1) associated with overall or subtype-specific breast cancer after gene-level correction for multiple testing. Rs11571215 in PGR (progesterone receptor) was the SNP most strongly associated with ER- disease. Conclusion We identified eight genes in hormone pathways that contain common variants associated with breast cancer in AA women after gene-level correction for multiple testing. PMID:26458823

  7. Hormone-related pathways and risk of breast cancer subtypes in African American women.

    PubMed

    Haddad, Stephen A; Lunetta, Kathryn L; Ruiz-Narváez, Edward A; Bensen, Jeannette T; Hong, Chi-Chen; Sucheston-Campbell, Lara E; Yao, Song; Bandera, Elisa V; Rosenberg, Lynn; Haiman, Christopher A; Troester, Melissa A; Ambrosone, Christine B; Palmer, Julie R

    2015-11-01

    We sought to investigate genetic variation in hormone pathways in relation to risk of overall and subtype-specific breast cancer in women of African ancestry (AA). Genotyping and imputation yielded data on 143,934 SNPs in 308 hormone-related genes for 3663 breast cancer cases (1098 ER-, 1983 ER+, 582 ER unknown) and 4687 controls from the African American Breast Cancer Epidemiology and Risk (AMBER) Consortium. AMBER includes data from four large studies of AA women: the Carolina Breast Cancer Study, the Women's Circle of Health Study, the Black Women's Health Study, and the Multiethnic Cohort Study. Pathway- and gene-based analyses were conducted, and single-SNP tests were run for the top genes. There were no strong associations at the pathway level. The most significantly associated genes were GHRH, CALM2, CETP, and AKR1C1 for overall breast cancer (gene-based nominal p ≤ 0.01); NR0B1, IGF2R, CALM2, CYP1B1, and GRB2 for ER+ breast cancer (p ≤ 0.02); and PGR, MAPK3, MAP3K1, and LHCGR for ER- disease (p ≤ 0.02). Single-SNP tests for SNPs with pairwise linkage disequilibrium r (2) < 0.8 in the top genes identified 12 common SNPs (in CALM2, CETP, NR0B1, IGF2R, CYP1B1, PGR, MAPK3, and MAP3K1) associated with overall or subtype-specific breast cancer after gene-level correction for multiple testing. Rs11571215 in PGR (progesterone receptor) was the SNP most strongly associated with ER- disease. We identified eight genes in hormone pathways that contain common variants associated with breast cancer in AA women after gene-level correction for multiple testing.

  8. Relation of plate kinematic parameters to deformation along the Andean margin from Late Jurassic to the present

    NASA Astrophysics Data System (ADS)

    Maloney, K. T.; Clarke, G. L.; Quevedo, L. E.; Klepeis, K. A.

    2011-12-01

    The geological consequences of temporal and spatial changes in subduction along the Andean margin from 170 Ma to the present were investigated in the context of a recently developed, global plate kinematic model. Geological events recorded by the overriding continental plate, including the development of extensional basins, orogeny and crustal growth accompanied by thickening and/or magmatism, were contrasted with the age of the subducting oceanic slab(s), the absolute plate velocity of South America both normal and parallel to the trench, and the relative convergence velocity between South America and the subducting slab(s) both normal and parallel to the trench. Preliminary results indicate that the absolute velocity of the overriding plate is strongly correlated with the extent of crustal extension; the development of marginal basins floored by oceanic crust occurred only when the absolute plate velocity of South America was directed away from the trench. This condition did not accompany the development of aborted marginal basins. An abrupt increase in relative convergence rates between the South American continent and the subducting slab also often accompanied the initiation of extension in the overriding plate. However, high convergence rates primarily accompanied the development of fold and thrust belts, and were linked with plateau uplift. Inter-dependencies between the various parameters are investigated to build a more complete model of conditions necessary for the development of significant geological events along continental margins controlled by subduction.

  9. Relative time scales reveal multiple origins of parallel disjunct distributions of African caecilian amphibians.

    PubMed

    Loader, Simon P; Pisani, Davide; Cotton, James A; Gower, David J; Day, Julia J; Wilkinson, Mark

    2007-10-22

    Parallel patterns of distribution in different lineages suggest a common cause. Explanations in terms of a single biogeographic event often imply contemporaneous diversifications. Phylogenies with absolute time scales provide the most obvious means of testing temporal components of biogeographic hypotheses but, in their absence, the sequence of diversification events and whether any could have been contemporaneous can be tested with relative date estimates. Tests using relative time scales have been largely overlooked, but because they do not require the calibration upon which absolute time scales depend, they make a large amount of existing molecular data of use to historical biogeography and may also be helpful when calibration is possible but uncertain. We illustrate the use of relative dating by testing the hypothesis that parallel, disjunct east/west distributions in three independent lineages of African caecilians have a common cause. We demonstrate that at least two biogeographic events are implied by molecular data. Relative dating analysis reveals the potential complexity of causes of parallel distributions and cautions against inferring common cause from common spatial patterns without considering the temporal dimension.

  10. Assessing Host-Virus Codivergence for Close Relatives of Merkel Cell Polyomavirus Infecting African Great Apes

    PubMed Central

    Madinda, Nadège F.; Ehlers, Bernhard; Wertheim, Joel O.; Akoua-Koffi, Chantal; Bergl, Richard A.; Boesch, Christophe; Akonkwa, Dieudonné Boji Mungu; Eckardt, Winnie; Fruth, Barbara; Gillespie, Thomas R.; Gray, Maryke; Hohmann, Gottfried; Karhemere, Stomy; Kujirakwinja, Deo; Langergraber, Kevin; Muyembe, Jean-Jacques; Nishuli, Radar; Pauly, Maude; Petrzelkova, Klara J.; Robbins, Martha M.; Todd, Angelique; Schubert, Grit; Stoinski, Tara S.; Wittig, Roman M.; Zuberbühler, Klaus; Peeters, Martine; Leendertz, Fabian H.

    2016-01-01

    ABSTRACT It has long been hypothesized that polyomaviruses (PyV; family Polyomaviridae) codiverged with their animal hosts. In contrast, recent analyses suggested that codivergence may only marginally influence the evolution of PyV. We reassess this question by focusing on a single lineage of PyV infecting hominine hosts, the Merkel cell polyomavirus (MCPyV) lineage. By characterizing the genetic diversity of these viruses in seven African great ape taxa, we show that they exhibit very strong host specificity. Reconciliation analyses identify more codivergence than noncodivergence events. In addition, we find that a number of host and PyV divergence events are synchronous. Collectively, our results support codivergence as the dominant process at play during the evolution of the MCPyV lineage. More generally, our results add to the growing body of evidence suggesting an ancient and stable association of PyV and their animal hosts. IMPORTANCE The processes involved in viral evolution and the interaction of viruses with their hosts are of great scientific interest and public health relevance. It has long been thought that the genetic diversity of double-stranded DNA viruses was generated over long periods of time, similar to typical host evolutionary timescales. This was also hypothesized for polyomaviruses (family Polyomaviridae), a group comprising several human pathogens, but this remains a point of controversy. Here, we investigate this question by focusing on a single lineage of polyomaviruses that infect both humans and their closest relatives, the African great apes. We show that these viruses exhibit considerable host specificity and that their evolution largely mirrors that of their hosts, suggesting that codivergence with their hosts played a major role in their diversification. Our results provide statistical evidence in favor of an association of polyomaviruses and their hosts over millions of years. PMID:27440885

  11. Minority-Related Stressors and Coping Processes among African American College Students

    ERIC Educational Resources Information Center

    Greer, Tawanda M.; Chwalisz, Kathleen

    2007-01-01

    This study is an investigation of stress and coping among African American students at a predominantly White college/university (PWCU) and a Historically Black College/University (HBCU) and their relationship to academic performance. Participants were 203 African American students (101 from a mid-size predominantly White midwestern state…

  12. Connective Complexity: African American Adolescents and the Relational Context of Kinship Foster Care

    ERIC Educational Resources Information Center

    Schwartz, Ann

    2008-01-01

    Attempts to address racial disproportionality in child welfare must include a focus on the benefits and challenges facing children in kinship care. African American children not only are overrepresented in the child welfare system, but also are placed disproportionately in kinship foster care. Using a sample of 18 African American adolescents ages…

  13. Negative and Positive Peer Influence: Relations to Positive and Negative Behaviors for African American, European American, and Hispanic Adolescents

    ERIC Educational Resources Information Center

    Padilla-Walker, Laura M.; Bean, Roy A.

    2009-01-01

    The purpose of the current study was to examine adolescents' perceptions of negative and positive peer influence (i.e., indirect peer association and direct peer pressure) as they related to adolescent behavior. Regression analyses were conducted using a sample of African American, European American, and Hispanic adolescents (N=1659, M age=16.06,…

  14. Adaptive and Challenged Parenting among African American Mothers: Parenting Profiles Relate to Head Start Children's Aggression and Hyperactivity

    ERIC Educational Resources Information Center

    Carpenter, Johanna L.; Mendez, Julia

    2013-01-01

    Research Findings: This study used a within-group research design and person-centered analytic methods to identify multidimensional profiles of parenting styles, parenting practices, and related emotional factors in a sample of 274 African American mothers recruited from Head Start programs in the northeastern and southeastern United States.…

  15. The Psychosocial Adjustment of African American Youth from Single Mother Homes: The Relative Contribution of Parents and Peers

    ERIC Educational Resources Information Center

    Chester, Charlene; Jones, Deborah J.; Zalot, Alecia; Sterrett, Emma

    2007-01-01

    This study examined the relative roles of parents and peers in the psychosocial adjustment of African American youth (7-15 years old) from single mother homes (N = 242). Main effects of both positive parenting and peer relationship quality were found for youth depressive symptoms. In addition, a main effect of peer relationship quality and an…

  16. Relations between Perceived Competence, Importance Ratings, and Self-Worth among African American School-Age Children

    ERIC Educational Resources Information Center

    Grier, Leslie K.

    2013-01-01

    The purpose of this research was to investigate how domain-specific importance ratings affect relations between perceived competence and self-worth among African American school-age children. Importance ratings have been found to affect the strength of the relationship between perceived competence and self-worth and have implications for…

  17. Mothers' Academic Gender Stereotypes and Education-Related Beliefs about Sons and Daughters in African American Families

    ERIC Educational Resources Information Center

    Wood, Dana; Kurtz-Costes, Beth; Rowley, Stephanie J.; Okeke-Adeyanju, Ndidi

    2010-01-01

    The role of African American mothers' academic gender stereotype endorsement in shaping achievement-related expectations for and perceptions of their own children was examined. Mothers (N = 334) of 7th and 8th graders completed measures of expectations for their children's future educational attainment, perceptions of their children's academic…

  18. Ethical review of health-related biotechnology research in Africa: a role for the Pan African Bioethics Initiative (PABIN).

    PubMed

    Petros, B

    2007-01-01

    The paper reviews the status of nature and functions of the Pan African Bioethics Initiative (PABIN) a voluntary organization, founded in 2001 by leading members of the African health research and bioethics communities, with the aim of enhancing ethical awareness in Africa, in general, and building ethical clearance capacity in all African countries in particular. PABIN, with a membership drawn from more than 20 African countries is a member of the forum of the WHO/TDR Strategic Initiative for Developing Capacity in Ethical Review (SIDCER). PABIN works closely with its sister forums in Asia, Latin America, Eastern Europe, and North America as well as other continental and international organizations that promote bioethics in health research. PABIN has conducted three conferences and several seminars in collaboration with continental and international partners on subjects of ethical concerns in Africa. Strategically, PABIN aims at assisting in the development of competent in-country bioethics review systems in all African countries. Notable among the contemporary issues that is on the PABIN agenda is addressing the repercussions of the active pursuit by pharmaceutical and other commercial interests from the Western developed countries to conduct all sorts of clinical biomedical trials on African populations before marketing such biotechnological products and services. This drive has brought with it highly controversial ethical issues at a time when both technical and organizational capacity are lacking in much of Africa to address the ethical concerns that are arising from some health-related researches. PABIN seeks to assure that the expected health and social benefits derivable from biotechnology are reaped in accordance with internationally accepted norms.

  19. A case-control study of menstrual factors in relation to breast cancer risk in African-American women.

    PubMed Central

    Beiler, Jessica S. B.; Zhu, Kangmin; Hunter, Sandra; Payne-Wilks, Kathleen; Roland, Chanel L.; Chinchilli, Vernon M.

    2003-01-01

    Menstrual characteristics may serve as surrogate measures of endogenous estrogen and may be related to breast cancer risk. No previous studies have systematically investigated menstrual factors in relation to the disease in African-American women. This case-control study is aimed to assess the relationship between menstrual factors and breast cancer in African-American women. Cases were 304 African-American women, aged 20-64 living in three Tennessee counties, diagnosed with breast cancer between 1995 and 1998. Controls were selected through random-digit dialing and frequency matched to cases (n=305). Phone interviews were conducted on menstrual factors--age at menarche, time to regularity, cycle length, flow length, age at menopause--and other risk factors. Logistic regression showed that compared to women with short cycle length (<28 days), women with average cycle length > or =28 had decreased risk of breast cancer (odds ratio (OR)=0.60, 95% confidence interval (CI), 0.38-0.94). Dose-response analyses showed decreasing risk with longer cycle length. Results by menopausal status revealed an inverse relationship was shown only in postmenopausal women. No significant associations were observed for other menstrual factors. Findings suggest that cycle length has an inverse association with breast cancer in African-American women that may primarily exist for post-menopausal tumors. PMID:14620704

  20. Developmental and ethnic issues experienced by emerging adult African American women related to developing a mature love relationship.

    PubMed

    Tyson, Sheryl Y

    2012-01-01

    This qualitative study explored perspectives of emerging adult African American women on the development of mature love relationships. Inductive analysis of focus group interviews, conducted with a purposive sample of 31 African American women, yielded themes related to relationship goals and characteristics, and interpersonal and societal challenges to finding the right partner and developing a mature love relationship. Core categories that emerged from analysis of the discussions were (1) age and relationship goal differences within the emerging adult group, (2) mature love relationship goals and characteristics, (3) interpersonal obstacles to finding the right partner, and (4) societal obstacles to finding the right partner. Two approaches-black womanist/feminist thought (Collins, 2000 ; Walker, 1983 ) and relationship maturity theory (Paul & White, 1990 )-were then combined to explain the influence of historic and contemporary interpersonal and societal factors on developmental and ethnic issues that challenge positive gender identity formation, hasten intimacy maturity, and hinder the development of mature love relationships among emerging adult African American women. For these women, premature responsibility, especially early caregiver burden, was related to the early development of intimacy capacity and the desire for a mature love relationship, to be protected, and to have someone to help carry the load. Interracial dating, negative stereotypic images of African American women, and even positive images of enduring black love relationships posed difficult challenges to positive identity formation and intimacy maturity. A primary challenge was to counteract negative stereotypic images, so that they could develop their own self-identities as women and as relationship partners.

  1. Coping Strategies as Moderators of the Relation between Individual Race-Related Stress and Mental Health Symptoms for African American Women

    ERIC Educational Resources Information Center

    Greer, Tawanda M.

    2011-01-01

    The purpose of this investigation was to examine coping strategies as moderators of the relationship between individual race-related stress and mental health symptoms among a sample of 128 African American women. Coping strategies refer to efforts used to resolve problems and those used to manage, endure, or alleviate distress. Culture-specific…

  2. Racial influences associated with weight-related beliefs in African American and Caucasian women.

    PubMed

    Malpede, Christie Z; Greene, Lori E; Fitzpatrick, Stephanie L; Jefferson, Wendy K; Shewchuk, Richard M; Baskin, Monica L; Ard, Jamy D

    2007-01-01

    This study examines African American and Caucasian women's perception of how race affects their weight. Structured focus groups that used the nominal group technique (NGT) were conducted with four groups of African American women (n = 30) and four groups of Caucasian women (n = 30). Participants generated responses to the question, "How does being a Black/White woman affect your weight?" The African American groups generated 48 unique ideas, including unhealthy food preparation, poor food selection habits, lack of exercise, stress, increased risk of chronic diseases, and associated medical costs; the Caucasian groups produced 32 responses, including distorted expectations of perfect body type, success depended on thinness and beauty, social pressures, media, and men's preferences. Results suggest that the African American women focused on food choices and health consequences while the Caucasian women emphasized body size and aesthetics. The observed differences support a need for culturally specific interventions that promote good eating patterns and healthy body shapes.

  3. Plate Tectonics Constrained by Evidence-Based Magmatic Temperatures and Phase Relations of Fertile Lherzolite (Invited)

    NASA Astrophysics Data System (ADS)

    Green, D. H.; Falloon, T.

    2010-12-01

    In order to understand Earth’s plate tectonics we must interpret the most direct probes for mantle composition and temperature distribution i.e. the primitive basaltic magmas and peridotites representing partial melts and mantle residues. An evidence-based approach to identification of parental magmas and determination of their temperatures requires glass and phenocryst compositions and experimentally calibrated Fe/Mg partitioning between olivine and melt. We have compared magmatic crystallization temperatures between ‘hot-spot’(proposed to be plume-related) and normal mid-ocean ridge basalt (MORB) parental liquids, by examining three representative magmatic suites from both ocean island (Hawaii, Iceland, and Réunion) and mid-ocean ridge settings (Cocos-Nazca, East Pacific Rise, and Mid-Atlantic Ridge). We have glass and olivine phenocryst compositions, including volatile (H2O) contents, and have calculated parental liquid compositions at 0.2GPa by incrementally adding olivine back into the glass compositions until a liquid in equilibrium with the most-magnesian olivine phenocryst composition is obtained. The results of these calculations demonstrate that there is very little difference (maximum of ~20°C) between the ranges of crystallization temperatures of the parental liquids (MORB:1243-1351°C versus OIB:1286-1372°C) when volatile contents are taken into account. However while lacking temperature contrast, the source regions for ‘hot-spot’ parental magmas contain geochemical signatures of old subducted crust/lithosphere. The mantle depths of origin determined for both the MORB and OIB suites are similar (MORB:1-2 GPa; OIB:1-2.5 GPa). Calculations of mantle potential temperatures (Tp) are model dependent, particularly to melt fraction from an inferred source. Assuming similar fertile lherzolite sources, the differences in Tp values between the hottest MORB and the hottest ocean island tholeiite sources are ~80°C. These differences disappear if the

  4. Health Emergency 2003: The Spread of Drug-Related AIDS and Hepatitis C among African American and Latinos. Health Emergency Series.

    ERIC Educational Resources Information Center

    Day, Dawn

    This report is the fifth in a series detailing the impact of the injection-related AIDS epidemic on African Americans and Latinos. Ten chapters include: (1) "Health Emergency: The Spread of AIDS among African Americans Who Inject Drugs"; (2) "Health Emergency: The Spread of AIDS Among Latinos Who Inject Drugs"; (3) "A…

  5. An intervention to reduce HIV-related stigma in partnership with African American and Latino churches.

    PubMed

    Derose, Kathryn Pitkin; Bogart, Laura M; Kanouse, David E; Felton, Alexandria; Collins, Deborah Owens; Mata, Michael A; Oden, Clyde W; Domínguez, Blanca X; Flórez, Karen R; Hawes-Dawson, Jennifer; Williams, Malcolm V

    2014-02-01

    HIV-related stigma negatively affects prevention and care, and community-based interventions are needed. Here we describe the development of a multi-ethnic, faith-based intervention to reduce HIV stigma that included: educational workshops on HIV, testing, and stigma; peer leader workshops using role plays and drawing on principles of motivational interviewing; a pastor-delivered sermon on HIV that incorporated theological reflection and an imagined contact scenario; and congregation-based HIV testing events. Lessons learned include: partnership development is essential and requires substantial investment; tailoring intervention components to single race-ethnic groups may not be preferable in diverse community settings; and adapting testing processes to be able to serve larger numbers of people in shorter time frames is needed for congregational settings. This development process successfully combined the rigorous application of social science theory and community engagement to yield a multifaceted HIV stigma reduction intervention appropriate for Protestant and Catholic churches in African American and Latino communities.

  6. AN INTERVENTION TO REDUCE HIV-RELATED STIGMA IN PARTNERSHIP WITH AFRICAN AMERICAN AND LATINO CHURCHES

    PubMed Central

    Derose, Kathryn Pitkin; Bogart, Laura M.; Kanouse, David E.; Felton, Alexandria; Collins, Deborah Owens; Mata, Michael A.; Oden, Clyde W.; Domínguez, Blanca X.; Flórez, Karen R.; Hawes-Dawson, Jennifer; Williams, Malcolm V.

    2014-01-01

    HIV-related stigma negatively affects prevention and care, and community-based interventions are needed. Here we describe the development of a multi-ethnic, faith-based intervention to reduce HIV stigma that included: educational workshops on HIV, testing, and stigma; peer leader workshops using role plays and drawing on principles of motivational interviewing; a pastor-delivered sermon on HIV that incorporated theological reflection and an imagined contact scenario; and congregation-based HIV testing events. Lessons learned include: partnership development is essential and requires substantial investment; tailoring intervention components to single race-ethnic groups may not be preferable in diverse community settings; and adapting testing processes to be able to serve larger numbers of people in shorter time frames is needed for congregational settings. This development process successfully combined the rigorous application of social science theory and community engagement to yield a multifaceted HIV stigma reduction intervention appropriate for Protestant and Catholic churches in African American and Latino communities. PMID:24450276

  7. Beliefs related to the use of oral contraceptives by African American women, ages 18-35.

    PubMed

    Libbus, K; Arps, C A

    1997-01-01

    This study looked at modal, salient beliefs regarding intention to use and use of oral contraceptives (OC) in a group of African American women aged 18-35 in a midwest urban community. Data were collected in face-to-face audio taped interviews using a format devised by Ajzen and Fishbein. Questions related to the identified behavior of deliberate action to avoid unwanted pregnancy by instituting the use of a contraceptive method. Twenty-five women consented to participate. Of these, 20 women (80%) reported using oral contraceptives as their primary birth control method. The study reports on women's perceptions of the advantages and disadvantages of OC acquisition and use and important social referents approving or disapproving of OC acquisition and use. Perceived barriers and facilitators to OC acquisition and use are also reported. Identification of individual and group attitudes regarding contraceptive behavior may be valuable in enhancing the provision of successful family planning services to women wishing to avoid delay of childbearing.

  8. Epiphyseal growth plate growth hormone receptor signaling is decreased in chronic kidney disease-related growth retardation.

    PubMed

    Troib, Ariel; Landau, Daniel; Kachko, Leonid; Rabkin, Ralph; Segev, Yael

    2013-11-01

    Linear growth retardation in children with chronic kidney disease (CKD) has been ascribed to insensitivity to growth hormone. This resistance state has been attributed to impaired growth hormone signaling through the JAK2/STAT5 pathway in liver and skeletal muscle leading to reduced insulin-like growth factor-I (IGF-I). Here we determine whether systemic and growth plate alterations in growth hormone signaling contribute to CKD-induced linear growth retardation using partially nephrectomized and pair-fed control 20-day-old rats. Serum growth hormone did not change in rats with CKD, yet serum IGF-I levels were decreased and growth retarded. The tibial growth plate hypertrophic zone was wider and vascularization at the primary ossification center was reduced in CKD. This was associated with a decrease in growth plate vascular endothelial growth factor (VEGF) mRNA and immunostainable VEGF and IGF-I levels. Growth plate growth hormone receptor and STAT5 protein levels were unchanged, while JAK2 was reduced. Despite comparable growth hormone and growth hormone receptor levels in CKD and control rats, relative STAT5 phosphorylation was significantly depressed in CKD. Of note, the mRNA of SOCS2, an inhibitor of growth hormone signaling, was increased. Thus, linear growth impairment in CKD can in part be explained by impaired long bone growth plate growth hormone receptor signaling through the JAK2/STAT5 pathway, an abnormality that may be caused by an increase in SOCS2 expression.

  9. Simultaneous modeling of habitat suitability, occupancy, and relative abundance: African elephants in Zimbabwe.

    PubMed

    Martin, Julien; Chamaillé-Jammes, Simon; Nichols, James D; Fritz, Hervé; Hines, James E; Fonnesbeck, Christopher J; MacKenzie, Darryl I; Bailey, Larissa L

    2010-06-01

    The recent development of statistical models such as dynamic site occupancy models provides the opportunity to address fairly complex management and conservation problems with relatively simple models. However, surprisingly few empirical studies have simultaneously modeled habitat suitability and occupancy status of organisms over large landscapes for management purposes. Joint modeling of these components is particularly important in the context of management of wild populations, as it provides a more coherent framework to investigate the population dynamics of organisms in space and time for the application of management decision tools. We applied such an approach to the study of water hole use by African elephants in Hwange National Park, Zimbabwe. Here we show how such methodology may be implemented and derive estimates of annual transition probabilities among three dry-season states for water holes: (1) unsuitable state (dry water holes with no elephants); (2) suitable state (water hole with water) with low abundance of elephants; and (3) suitable state with high abundance of elephants. We found that annual rainfall and the number of neighboring water holes influenced the transition probabilities among these three states. Because of an increase in elephant densities in the park during the study period, we also found that transition probabilities from low abundance to high abundance states increased over time. The application of the joint habitat-occupancy models provides a coherent framework to examine how habitat suitability and factors that affect habitat suitability influence the distribution and abundance of organisms. We discuss how these simple models can further be used to apply structured decision-making tools in order to derive decisions that are optimal relative to specified management objectives. The modeling framework presented in this paper should be applicable to a wide range of existing data sets and should help to address important ecological

  10. Comparing HIV-related symbolic stigma in six African countries: social representations in young people's narratives.

    PubMed

    Winskell, Kate; Hill, Elizabeth; Obyerodhyambo, Oby

    2011-10-01

    HIV-related symbolic stigma arises from moralistic value judgements attached to people living with HIV and has negative consequences from both public health and human rights perspectives. Relatively little is known about cross-national variation in symbolic stigma. With the purpose of informing stigma reduction efforts within and across settings, we compared social representations of HIV in six African countries with estimated adult HIV prevalence rates ranging from 1 to 33%. Our study used a unique data source, namely a stratified random sample (n = 586, ∼5%) from 11,354 creative ideas contributed from six countries to a continent-wide HIV-related scriptwriting contest held between February and April 2005. The narratives were written by equal numbers of males and females aged 10-24 in urban and rural areas of Swaziland, Namibia, Kenya, South-East Nigeria, Burkina Faso and Senegal. We combined three analytical approaches: descriptive statistics on certain quantifiable characteristics of the narratives, thematic data analysis, and a narrative-based approach. The association of HIV with outsiders ("othering") and preoccupation with the circumstances of infection are more common in lower prevalence countries but vary substantially in tone depending on the sociocultural context. The highest proportion both of moralising narratives and of narratives with pessimistic outcomes come from South-East Nigeria and, to a lesser extent, from Kenya, countries with prevalence levels of 3.9 and 6.1% respectively, in which evangelical Christian movements, including Pentecostalism, have sizeable followings. The data provide a rare cross-cultural overview of symbolic stigma, identify country-specific needs, and point to strategies for future programming. Social representations from the highest prevalence countries, Swaziland and Namibia, and from lower prevalence Burkina Faso offer potential models for the framing of HIV in ways that serve to increase social proximity and counteract

  11. Simultaneous modeling of habitat suitability, occupancy, and relative abundance: African elephants in Zimbabwe

    USGS Publications Warehouse

    Martin, Julien; Chamaille-Jammes, Simon; Nichols, James D.; Fritz, Herve; Hines, James E.; Fonnesbeck, Christopher J.; MacKenzie, Darryl I.; Bailey, Larissa L.

    2010-01-01

    The recent development of statistical models such as dynamic site occupancy models provides the opportunity to address fairly complex management and conservation problems with relatively simple models. However, surprisingly few empirical studies have simultaneously modeled habitat suitability and occupancy status of organisms over large landscapes for management purposes. Joint modeling of these components is particularly important in the context of management of wild populations, as it provides a more coherent framework to investigate the population dynamics of organisms in space and time for the application of management decision tools. We applied such an approach to the study of water hole use by African elephants in Hwange National Park, Zimbabwe. Here we show how such methodology may be implemented and derive estimates of annual transition probabilities among three dry-season states for water holes: (1) unsuitable state (dry water holes with no elephants); (2) suitable state (water hole with water) with low abundance of elephants; and (3) suitable state with high abundance of elephants. We found that annual rainfall and the number of neighboring water holes influenced the transition probabilities among these three states. Because of an increase in elephant densities in the park during the study period, we also found that transition probabilities from low abundance to high abundance states increased over time. The application of the joint habitat–occupancy models provides a coherent framework to examine how habitat suitability and factors that affect habitat suitability influence the distribution and abundance of organisms. We discuss how these simple models can further be used to apply structured decision-making tools in order to derive decisions that are optimal relative to specified management objectives. The modeling framework presented in this paper should be applicable to a wide range of existing data sets and should help to address important ecological

  12. New Evidence that the Emperor Seamount Chain Records Motion of the Pacific Plate Relative to the Deep Mantle

    NASA Astrophysics Data System (ADS)

    Gordon, Richard; Seidman, Lily

    2016-04-01

    A key question for Pacific and circum-Pacific tectonics with implications for mantle convection is whether the Emperor seamount chain records the northward motion of the Pacific plate relative to the deep mantle. To investigate this question, we determine a new Pacific plate paleomagnetic pole for ≈60 Ma BP from the analysis of the skewness of marine magnetic anomaly 26r recording Pacific-Farallon motion in low paleolatitudes. We further update a previously published Pacific plate pole for ≈65 Ma from the analysis of anomalies 27r to 31 by incorporating a larger correction for anomalous skewness. These two poles, along with prior poles for 58 Ma and 72 Ma allow us to test how much, if any, the Hawaiian hotspot moved relative to the spin axis for ≈14 Ma of the ≈30 Ma during which the Emperor chain was formed. We find that the Hawaiian hotspot moved insignificantly southward (4 ±17 mm/a (95% confidence limits)) from 72 Ma to 58 Ma while the Pacific plate moved significantly northward (42 ± 17 mm/a (95% confidence limits)). We further compare the apparent polar wander of the Pacific hotspots with that of the Indo-Atlantic hotspots over the past 65 Ma. The two paths indicate a jump of ≈8° in the position of the spin axis relative to global hotspots between ≈60 Ma and ≈45 Ma presumably due to true polar wander.

  13. Differential Persistence of Foot-and-Mouth Disease Virus in African Buffalo Is Related to Virus Virulence

    PubMed Central

    Maree, Francois; de Klerk-Lorist, Lin-Mari; Gubbins, Simon; Zhang, Fuquan; Seago, Julian; Pérez-Martín, Eva; Reid, Liz; Scott, Katherine; van Schalkwyk, Louis; Bengis, Roy; Juleff, Nicholas

    2016-01-01

    ABSTRACT Foot-and-mouth disease (FMD) virus (FMDV) circulates as multiple serotypes and strains in many regions of endemicity. In particular, the three Southern African Territories (SAT) serotypes are maintained effectively in their wildlife reservoir, the African buffalo, and individuals may harbor multiple SAT serotypes for extended periods in the pharyngeal region. However, the exact site and mechanism for persistence remain unclear. FMD in buffaloes offers a unique opportunity to study FMDV persistence, as transmission from carrier ruminants has convincingly been demonstrated for only this species. Following coinfection of naive African buffaloes with isolates of three SAT serotypes from field buffaloes, palatine tonsil swabs were the sample of choice for recovering infectious FMDV up to 400 days postinfection (dpi). Postmortem examination identified infectious virus for up to 185 dpi and viral genomes for up to 400 dpi in lymphoid tissues of the head and neck, focused mainly in germinal centers. Interestingly, viral persistence in vivo was not homogenous, and the SAT-1 isolate persisted longer than the SAT-2 and SAT-3 isolates. Coinfection and passage of these SAT isolates in goat and buffalo cell lines demonstrated a direct correlation between persistence and cell-killing capacity. These data suggest that FMDV persistence occurs in the germinal centers of lymphoid tissue but that the duration of persistence is related to virus replication and cell-killing capacity. IMPORTANCE Foot-and-mouth disease virus (FMDV) causes a highly contagious acute vesicular disease in domestic livestock and wildlife species. African buffaloes (Syncerus caffer) are the primary carrier hosts of FMDV in African savannah ecosystems, where the disease is endemic. We have shown that the virus persists for up to 400 days in buffaloes and that there is competition between viruses during mixed infections. There was similar competition in cell culture: viruses that killed cells quickly

  14. Trichotillomania symptoms in African American women: are they related to anxiety and culture?

    PubMed

    Neal-Barnett, Angela; Statom, Deborah; Stadulis, Robert

    2011-08-01

    Trichotillomania (TTM) is a little understood disorder that has been underresearched in the African American community. Furthermore, the incorporation of cultural factors into TTM research has virtually been ignored. Existing data from an African American college student population suggest TTM is associated with high levels of anxiety. In this study, we explored anxiety symptoms and cultural hair messages in an African American female community sample with TTM symptoms. We predicted high levels of TTM severity and impairment would be associated with high level of anxiety symptoms. We also predicted that cultural messages about hair will influence both TTM and anxiety symptoms. In this telephone study, 41 African American females participated in interviews about their TTM. TTM impairment and severity was positively correlated with general anxiety symptoms as measured on the Symptom Checklist 90-Revised (SCL 90-R(®) ). Severity was also positively correlated with obsessive-compulsive symptoms. Given the significance of hair for African American women, we also explored the childhood cultural messages receive about hair. Over half the sample received at least one cultural message about hair. Although many women received the same message, the value they placed on the message differed. Messages received about hair were not associated with TTM severity or impairment. The association among obsessive-compulsive symptoms and hair messages approached significance. Results highlight the importance of assessing anxiety comorbidity and culture with African American TTM samples. Little is known about TTM in African American samples. Existing research indicates this population seeks TTM help from their hairdressers. Among college students, a significant correlation has been found for anxiety as measured on the Beck Anxiety Inventory and TTM. To the best of our knowledge, this is the first paper to examine cultural messages about hair in an African American sample. In addition

  15. Space use of African wild dogs in relation to other large carnivores.

    PubMed

    Darnell, Angela M; Graf, Jan A; Somers, Michael J; Slotow, Rob; Szykman Gunther, Micaela

    2014-01-01

    Interaction among species through competition is a principle process structuring ecological communities, affecting behavior, distribution, and ultimately the population dynamics of species. High competition among large African carnivores, associated with extensive diet overlap, manifests in interactions between subordinate African wild dogs (Lycaon pictus) and dominant lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Using locations of large carnivores in Hluhluwe-iMfolozi Park, South Africa, we found different responses from wild dogs to their two main competitors. Wild dogs avoided lions, particularly during denning, through a combination of spatial and temporal avoidance. However, wild dogs did not exhibit spatial or temporal avoidance of spotted hyenas, likely because wild dog pack sizes were large enough to adequately defend their kills. Understanding that larger carnivores affect the movements and space use of other carnivores is important for managing current small and fragmented carnivore populations, especially as reintroductions and translocations are essential tools used for the survival of endangered species, as with African wild dogs.

  16. FACTORS RELATED TO HIV TESTING AMONG AN AFRICAN AMERICAN CHURCH-AFFILIATED POPULATION

    PubMed Central

    Berkley-Patton, Jannette; Moore, Erin W.; Hawes, Starlyn M.; Thompson, Carole Bowe; Bohn, Alexandria

    2014-01-01

    HIV continues to disproportionately impact communities of color, and more calls are being extended to African American churches to assist in HIV education and screening efforts. However, no studies have reported on the HIV testing practices of African American church-affiliated persons. This study examines demographic, social, and behavioral factors associated with ever receiving an HIV test and last 12-month HIV testing. Findings indicated not having insurance and condom use were predictors of ever receiving an HIV test. Predictors of HIV testing in the last 12 months included marital status (i.e., single, divorced, separated, or widowed) and intentions to get tested for HIV in the near future. These predictors should be considered when designing HIV education and screening interventions for African American church settings. PMID:22468975

  17. Human papillomavirus and human immunodeficiency virus infections: relation with cervical dysplasia-neoplasia in African women.

    PubMed

    La Ruche, G; You, B; Mensah-Ado, I; Bergeron, C; Montcho, C; Ramon, R; Touré-Coulibaly, K; Welffens-Ekra, C; Dabis, F; Orth, G

    1998-05-18

    Our study assessed the factors associated with cervical squamous intra-epithelial lesions (SILs) and invasive cervical cancer, with special attention to human immunodeficiency virus (HIV) and human papillomavirus (HPV) infections. Women from 3 outpatient gynecology clinics of Abidjan, Côte d'Ivoire, were screened for cervical abnormalities: 151 women with low-grade SILs and 151 controls, 60 with high-grade SILs and 240 controls, and 13 with invasive cancer and 65 controls were enrolled in 3 case-control studies. Controls were chosen at random among the women without lesions, with a frequency matching for age and center. We used the PCR method for the detection of cervical HPV DNA and the restriction fragment length polymorphism analysis for HPV typing. HIV antibody testing and CD4 cell count were performed. In multivariate analyses, factors associated with cervical lesions were: for low-grade SILs, HPV positivity, HIV-1 seropositivity and parity >3; for high-grade SILs, HPV positivity, chewing tobacco, HIV-1 seropositivity and illiteracy, and for invasive cancer, HPV positivity only. We found a diversity of HPV types associated with SILs. In HIV-1-infected women, SILs occurred at an early stage of HIV disease. Women infected with both HIV-1 and HPV were at much higher risk of SILs than women infected with each of these 2 viruses separately. Invasive cancer was linked to HIV-2 infection in univariate analysis only. Our results suggest that the relation of SILs with HIV-1 infection is mainly explained by HPV infection and that HIV-1-infected African women may not often reach the invasive stage of cervical cancer.

  18. Variants of estrogen-related genes and breast cancer risk in European and African American women.

    PubMed

    Quan, Lei; Hong, Chi-Chen; Zirpoli, Gary; Roberts, Michelle R; Khoury, Thaer; Sucheston-Campbell, Lara E; Bovbjerg, Dana H; Jandorf, Lina; Pawlish, Karen; Ciupak, Gregory; Davis, Warren; Bandera, Elisa V; Ambrosone, Christine B; Yao, Song

    2014-01-01

    It has been observed previously that compared with women of European ancestry (EA), those of African ancestry (AA) are more likely to develop estrogen receptor (ER)-negative breast cancer, although the mechanisms have not been elucidated. We tested the associations between breast cancer risk and a targeted set of 20 genes known to be involved in estrogen synthesis, metabolism, and response and potential gene-environment interactions using data and samples from 1307 EA (658 cases) and 1365 AA (621 cases) participants from the Women's Circle of Health Study (WCHS). Multivariable logistic regression found evidence of associations with single-nucleotide polymorphisms (SNPs) in the ESR1 gene in EA women (rs1801132, odds ratio (OR)=1.47, 95% CI=1.20-1.80, P=0.0002; rs2046210, OR=1.24, 95% CI=1.04-1.47, P=0.02; and rs3020314, OR=1.43, 95% CI=1.19-1.70, P=0.00009), but not in AA women. The only other gene associated with breast cancer risk was CYP1A2 in AA women (rs2470893, OR=1.42, 95% CI=1.00-2.02, P=0.05), but not in EA women. When stratified by ER status, ESR1 rs1801132, rs2046210, and rs3020314 showed stronger associations in ER-positive than in ER-negative breast cancer in only EA women. Associations with the ESR1 SNPs in EA women also appeared to be stronger with longer endogenous estrogen exposure or hormonal replacement therapy use. Our results indicate that there may be differential genetic influences on breast cancer risk in EA compared with AA women and that these differences may be modified by tumor subtype and estrogen exposures. Future studies with a larger sample size may determine the full contribution of estrogen-related genes to racial/ethnic differences in breast cancer.

  19. A critical approach to stress-related disorders in African Americans.

    PubMed Central

    Mattis, J. S.; Bell, C. C.; Jagers, R. J.; Jenkins, E.

    1999-01-01

    This article outlines an integrative, dynamic approach to stress and is, in part, a response to emergent debates within social science research and practice that suggest that African Americans are currently experiencing the reverberating psychological effects of slavery and oppression. It is the product of the work of an African-American mental health think tank situated at the Community Mental Health Council, Chicago, Illinois. We suggest the need to attend to biopsychosocial, environmental, and cultural factors that inform both exposure and responses to stress. Finally, consideration is given to matters of resiliency. PMID:10083776

  20. Kinematics of the New Zealand plate boundary: Relative motion by GPS across networks of 1000 km and 50 km spacing

    NASA Technical Reports Server (NTRS)

    Meertens, Charles M.; Rocken, Christian; Perin, Barbara; Walcott, Richard

    1993-01-01

    The NASA/DOSE 'Kinematics of the New Zealand Plate Boundary' experiment is a four-year cooperative Global Positioning System (GPS) experiment involving 6 universities and institutions in New Zealand and the United States. The investigation covers two scales, the first on the scale of plates (approximately 1000 km) and the second is on the scale of the plate boundary zone (approximately 50 km). In the first portion of the experiment, phase A, the objective is to make direct measurements of tectonic plate motion between the Australian and Pacific plates using GPS in order to determine the Euler vector of this plate pair. The phase A portion of this experiment was initiated in December 1992 with the first-epoch baseline measurements on the large scale network. The network will be resurveyed two years later to obtain velocities. The stations which were observed for phase A are shown and listed. Additional regional stations which will be used for this study are listed and are part of either CIGNET or other global tracking networks. The phase A portion of the experiment is primarily the responsibility of the UNAVCO investigators. Therefore, this report concentrates on phase A. The first year of NASA funding for phase A included only support for the field work. Processing and analysis will take place with the second year of funding. The second part of the experiemnt measured relative motion between the Australian and Pacific plates across the pate boundary zone between Hokitika and Christchurch on the South Island of New Zealand. The extent and rate of deformation will be determined by comparisons with historical, conventional surveys and by repeated GPS measurements to be made in two years. This activity was the emphasis of the LDGO portion of the study. An ancillary experiment, phase C, concentrated on plate boundary deformation in the vicinity of Wellington and was done as part of training during the early portion of the field campaign. Details of the objectives of the

  1. The effects of plate-bending-related aquifer thickening on temperatures in the Japan Trench subduction zone

    NASA Astrophysics Data System (ADS)

    Spinelli, G. A.

    2015-12-01

    Accurate subduction zone thermal models are necessary to understand a wide range of geophysical and geochemical processes, including: metamorphic reaction progress, mantle wedge hydration, and melt generation. For decades, plate convergence rate and subducting plate age and dip have been recognized as basic factors affecting subduction zone temperatures. Recent discoveries highlight the important effects of fluid circulation in oceanic lithosphere on subduction zone temperatures. However, there are contrasting hypotheses for the distribution of the regions within the oceanic lithosphere that host vigorous fluid circulation: one with a constant thickness aquifer extending both seaward and landward of the trench, one with an aquifer that thickens as it approaches the trench (due to bend-related faulting) but assumes vigorous fluid circulation only occurs prior to subduction, and a hybrid that considers both aquifer thickening seaward of the trench and continued circulation in the subducting plate. I examine the effects of bend-related aquifer thickening on temperatures within the Japan Trench subduction zone with a suite of thermal models. Kawada et al. [2014] hypothesize that plate-bending faults offshore northern Japan increase the thickness of the oceanic crustal aquifer, and therefore influence heat redistribution in the system. Existing models explore the effects of aquifer thickening on heat flux seaward of the trench, but they do not examine the effects of this process on temperatures within the subduction zone; additionally, they treat the aquifer seaward of the trench as completely isolated from the aquifer in the subducted plate. Here, I exploit the fact that aquifer thickening from the outer rise to the trench and continued fluid circulation in subducting crust are expected to produce distinct surface heat flux anomalies, in order to constrain the thermal effects of each process. I find the combinations of the amount of aquifer thickening and the degree of

  2. The Prevalence of and Factors Associated with Alcohol-Related Problems in a Community Sample of African American Women

    PubMed Central

    Elifson, Kirk W.

    2016-01-01

    Purpose. This study examines the prevalence of alcohol-related problems, the factors underlying these problems, and whether or not there is evidence of syndemic effects in a community population of southern, urban African American women. Methods. Questionnaire-based interviews were conducted with 817 women, all African American, from 80 targeted census block groups in Atlanta, Georgia. Results. Most of the alcohol users (67.8%) experienced at least one problem as a result of their alcohol (ab)use, with most women experiencing two or more such problems. Eight factors were found to be associated with experiencing more alcohol problems: being aged 30 or older, having had no recent health insurance, lower levels of educational attainment, self-identifying as lesbian or bisexual, experiencing greater amounts of childhood maltreatment, greater impulsivity, perceiving one's local community or neighborhood to be unsafe, and having a larger number of criminally involved friends. Conclusions. Drinking-related problems were prevalent in this population. Numerous factors underlie the extent to which African American women experienced problems resulting from their alcohol use. There is strong evidence of syndemic-type effects influencing drinking problems in this population, and future efforts to reduce the negative impact of alcohol (ab)use ought to consider the adoption of programs using a syndemics' theory approach. PMID:27752388

  3. Relative potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications

    NASA Technical Reports Server (NTRS)

    Borden, C. S.; Schwartz, D. L.

    1984-01-01

    The purpose of this study is to assess the relative economic potentials of concenrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications in the mid-1990's. Specific objectives of this study are to provide information on concentrator photovoltaic collector probabilistic price and efficiency levels to illustrate critical areas of R&D for concentrator cells and collectors, and to compare concentrator and flat-plate PV price and efficiency alternatives for several locations, based on their implied costs of energy. To deal with the uncertainties surrounding research and development activities in general, a probabilistic assessment of commercially achievable concentrator photovoltaic collector efficiencies and prices (at the factory loading dock) is performed. The results of this projection of concentrator photovoltaic technology are then compared with a previous flat-plate module price analysis (performed early in 1983). To focus this analysis on specific collector alternatives and their implied energy costs for different locations, similar two-axis tracking designs are assumed for both concentrator and flat-plate options.

  4. Responding to AIDS-Related Bereavement in the South African Context

    ERIC Educational Resources Information Center

    Demmer, Craig

    2007-01-01

    AIDS continues to be a death sentence for many individuals living in South Africa where it remains the leading cause of death. Little is currently known about what it is like to experience the loss of a loved one to AIDS from the South African perspective and how to assist individuals who are living in a context vastly different from similarly…

  5. Lexicon size and its relation to foot preference in the African grey parrot (Psittacus erithacus).

    PubMed

    Snyder, P J; Harris, L J

    1997-06-01

    To study footedness in parrots, an international survey of parrot owners was conducted. Responses were obtained from 524 individuals, including 70 owners of African Grey parrots (all animals > or = 10 months old). All respondents were given a 10-item questionnaire and a standard method for testing foot preference in their pets, and they were asked to count the number of separate words in their pets' lexicons of human speech sounds. Right-footed African Greys (N = 36) had significantly larger lexicons than left-footed African Greys (N = 34; P = 0.01). This difference could not be accounted for by group differences in training efforts or socialization/housing with conspecifics. A non-significant trend in the same direction was found in a comparison sample of Amazon parrots, although these genera are less adept than African Greys at learning human speech sounds. Other investigators have provided convincing evidence of lateralization, in the avian brain, for the analysis and memory of differing types of stimuli. In addition, there appears to be preferential left hypserstriatal activation for long-term memory consolidation. Our results suggest a relationship between lateral asymmetry for motor preference and asymmetric CNS mediation of a 'higher cognitive' function (i.e. the categorization and long-term mnestic processing of human speech sound.

  6. Civic Engagement in Relation to Outcome Expectations among African American Young Adults

    ERIC Educational Resources Information Center

    Chung, He Len; Probert, Stephanie

    2011-01-01

    The present study examined civic engagement--volunteering and political activism--among 129 African American young adults from an urban community. The proposed model considered factors that motivate young adults to participate in civic activities as well as barriers that might inhibit involvement. Drawing upon social cognitive theory, this study…

  7. Factors Related to College Going Self-Efficacy among Urban African American High School Students

    ERIC Educational Resources Information Center

    McKechnie, Jessica Diaz

    2012-01-01

    This study examined the relationship between college-going self-efficacy and high school students' perceived levels of achievement goal orientations (mastery-approach, performance-approach, performance-avoidance), vocational identity, need for occupational information, and barriers to occupational goals for a sample of African American urban…

  8. Prevention-Related Research Targeting African American Alternative Education Program Students

    ERIC Educational Resources Information Center

    Carswell, Steven B.; Hanlon, Thomas E.; Watts, Amy M.; O'Grady, Kevin E.

    2014-01-01

    This article reports on a program of research that examined the background, planning, implementation, and evaluation of an after-school preventive intervention program within an ongoing urban alternative education program targeting African American students referred to the school because of their problematic behavior in regular schools. The…

  9. Friendships Influence Hispanic Students' Implicit Attitudes toward White Non-Hispanics Relative to African Americans

    ERIC Educational Resources Information Center

    Aberson, Christopher L.; Porter, Michael K.; Gaffney, Amber M.

    2008-01-01

    This study examined the role of Hispanic students' friendships with White non-Hispanics (n-Hs) and African Americans (AAs) in predicting implicit and explicit prejudices toward these groups. Participants (N = 73) completed implicit and explicit attitude measures and a friendship questionnaire. Friendships were associated with implicit attitudes…

  10. Vibration of a delaminated beam-plate relative to buckled states

    NASA Astrophysics Data System (ADS)

    Yin, W.-L.; Jane, K. C.

    1992-07-01

    Free vibrations of delaminated beam-plates with respect to postbuckled referential states are studied. If the postbuckling deformation of the referential state is symmetric with respect to the mid-point, then the symmetric and antisymmetric vibration modes are uncoupled. Short delaminations which do not significantly degradate the overall stiffness of the beam-plate have little effect on the lowest modes of vibration and their frequencies, while the presence of a long delamination generally introduces additional vibration frequencies, the associated mode shapes of which show out-of-phase motions of the upper and lower delaminated layers. These new vibration modes and frequencies depend sensitively on the delamination length and location and on the magnitude of the postbuckling load. Hence their detection may indicate the presence and the nature of internal delamination damage.

  11. Forced relative displacements of the core and mantle as the basic mechanism of secular changes of the Earth shape and lithosphere plates tectonics

    NASA Astrophysics Data System (ADS)

    Barkin, Yury

    2010-05-01

    The summary. In the work planetary changes of a figure of the Earth and geoid in present epoch are discussed. Contrast and asymmetric geodetic changes of northern and southern hemispheres are revealed. The phenomenon of lengthening of latitude circles of a southern hemisphere and shortening of lengths of latitude circles of northern hemisphere, the phenomenon of expansion of a southern hemisphere and, accordingly, compression of northern hemisphere in relation to the center of mass of the Earth have been predicted. The reasons of the planetary tendency of displacement (drift) of plates in northern direction are studied. The geodynamic model is developed, on which the basic moving force in tectonics of plates is a gravitational influence of a moveable core of the Earth on all layers of the mantle, and also on blocks of the crust and lithosphere plates. In a base of all tectonic and geological reorganizations the mechanism of the forced relative oscillations and swings of the core and the mantle of the Earth in various time scales, including geological timescale lays. 1 Mechanism of formation and changes of the pear-shaped form of the Earth. According to developed geodynamic model a pear-shaped form of planets is not their given property for all time (as believed before scientists), and is the dynamic response to the slow forced relative displacements of the core and mantle [1]. Than more a relative displacement of the core and mantle (eccentricity of the core in some geology epoch), is especially clearly expressed pear-shaped form. The planet Mars possesses a big pear-shaped form and by our estimations the core of this planet is displaced in northern direction (to latitude in approximately 60° N) on 20-25 km [2]. An eccentricity of the Earth core is less (estimations give displacement about 3-4 km in direction to Brazil [3]) and it pear-shaped form is much less. 2 The phenomenon of asymmetric lengthening of latitude circles of southern and northern hemispheres of

  12. East African Rift Valley, Kenya

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground.

  13. Grade-related changes in the production of African American English.

    PubMed

    Craig, Holly K; Washington, Julie A

    2004-04-01

    This investigation examined grade as a source of systematic variation in the African American English (AAE) produced by students in preschool through fifth grades. Participants were 400 typically developing African American boys and girls residing in low- or middle-income homes in an urban-fringe community or midsize central city in the metropolitan Detroit area. Between preschoolers and kindergartners, and between first through fifth graders, there were no significant differences in the amounts of dialect produced during a picture description language elicitation context. However, there was a significant downward shift in dialect production at first grade. Students who evidenced dialect shifting outperformed their nonshifting peers on standardized tests of reading achievement and vocabulary breadth.

  14. Improved PCR Methods for Detection of African Rabies and Rabies-Related Lyssaviruses ▿

    PubMed Central

    Coertse, Jessica; Weyer, Jacqueline; Nel, Louis H.; Markotter, Wanda

    2010-01-01

    Eleven different lyssavirus species, four of which occur on the African continent, are presently recognized. These viruses cause rabies, the burden of which is highest in the developing world, where routine laboratory diagnosis is often not available. From an epidemiological and control perspective, it is necessary that diagnostic methods detect the diversity of lyssaviruses present in different regions of the world. A published and widely used heminested reverse transcription-PCR (hnRT-PCR) was evaluated for its ability to detect a panel of diverse African lyssaviruses. Due to the limitations experienced for this assay, an alternative hnRT-PCR was developed. The new assay was found to be accurate and sensitive in the detection of African lyssavirus RNA in a variety of clinical specimens. The assay was further adapted to a real-time PCR platform to allow rapid, one-step, quantitative, and single-probe detection, and an internal control for the verification of sample preparation was included. The limit of detection of the real-time PCR assay was 10 RNA copies per reaction, with inter- and intra-assay variability below 4%. Subsequently, in demonstrating utility, both assays were successfully applied to antemortem rabies diagnosis in humans. We believe that the quantitative real-time PCR assay could find application as a routine confirmatory test for rabies diagnosis in the future and that it will serve as a valuable research tool in the biology of African lyssaviruses. Alternatively, the hnRT-PCR assay can be used in laboratories that do not have access to expensive real-time PCR equipment for sensitive diagnosis of lyssaviruses. PMID:20810772

  15. Space Use of African Wild Dogs in Relation to Other Large Carnivores

    PubMed Central

    Darnell, Angela M.; Graf, Jan A.; Somers, Michael J.; Slotow, Rob; Szykman Gunther, Micaela

    2014-01-01

    Interaction among species through competition is a principle process structuring ecological communities, affecting behavior, distribution, and ultimately the population dynamics of species. High competition among large African carnivores, associated with extensive diet overlap, manifests in interactions between subordinate African wild dogs (Lycaon pictus) and dominant lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Using locations of large carnivores in Hluhluwe-iMfolozi Park, South Africa, we found different responses from wild dogs to their two main competitors. Wild dogs avoided lions, particularly during denning, through a combination of spatial and temporal avoidance. However, wild dogs did not exhibit spatial or temporal avoidance of spotted hyenas, likely because wild dog pack sizes were large enough to adequately defend their kills. Understanding that larger carnivores affect the movements and space use of other carnivores is important for managing current small and fragmented carnivore populations, especially as reintroductions and translocations are essential tools used for the survival of endangered species, as with African wild dogs. PMID:24896638

  16. Mantle-derived peridotites in southwestern Oregon: relation to plate tectonics.

    PubMed

    Medaris, L G; Dott, R H

    1970-09-04

    A group of peridotites in southwestern Oregon contains high-pressure mineral assemblages reflecting recrystallization at high temperatures (1100 degrees to 1200 degrees C) over a range of pressure decreasing from 19 to 5 kilobars. It is proposed that the peridotites represent upper-mantle material brought from depth along the ancestral Gorda-Juan de Fuca ridge system, transported eastward by the spreading Gorda lithosphere plate, and then emplaced by thrust-faulting in the western margin of the Cordillera during late Mesozoic time.

  17. On the relations between cratonic lithosphere thickness, plate motions, and basal drag

    USGS Publications Warehouse

    Artemieva, I.M.; Mooney, W.D.

    2002-01-01

    An overview of seismic, thermal, and petrological evidence on the structure of Precambrian lithosphere suggests that its local maximum thickness is highly variable (140-350 km), with a bimodal distribution for Archean cratons (200-220 km and 300-350 km). We discuss the origin of such large differences in lithospheric thickness, and propose that the lithospheric base can have large depth variations over short distances. The topography of Bryce Canyon (western USA) is proposed as an inverted analog of the base of the lithosphere. The horizontal and vertical dimensions of Archean cratons are strongly correlated: larger cratons have thicker lithosphere. Analysis of the bimodal distribution of lithospheric thickness in Archean cratons shows that the "critical" surface area for cratons to have thick (>300 km) keels is >6-8 ?? 106 km2 . Extrapolation of the linear trend between Archean lithospheric thickness and cratonic area to zero area yields a thickness of 180 km. This implies that the reworking of Archean crust should be accompanied by thinning and reworking of the entire lithospheric column to a thickness of 180 km in accord with thickness estimates for Proterozoic lithosphere. Likewise, extrapolation of the same trend to the size equal to the total area of all Archean cratons implies that the lithospheric thickness of a hypothesized early Archean supercontinent could have been 350-450 km decreasing to 280-400 km for Gondwanaland. We evaluate the basal drag model as a possible mechanism that may thin the cratonic lithosphere. Inverse correlations are found between lithospheric thickness and (a) fractional subduction length and (b) the effective ridge length. In agreement with theoretical predictions, lithospheric thickness of Archean keels is proportional to the square root of the ratio of the craton length (along the direction of plate motion) to the plate velocity. Large cratons with thick keels and low plate velocities are less eroded by basal drag than small

  18. Prospective Relations among Low-Income African American Adolescents' Maternal Attachment Security, Self-Worth, and Risk Behaviors.

    PubMed

    Lockhart, Ginger; Phillips, Samantha; Bolland, Anneliese; Delgado, Melissa; Tietjen, Juliet; Bolland, John

    2017-01-01

    This study examined prospective mediating relations among mother-adolescent attachment security, self-worth, and risk behaviors, including substance use and violence, across ages 13-17 in a sample of 901 low-income African American adolescents. Path analyses revealed that self-worth was a significant mediator between attachment security and risk behaviors, such that earlier attachment security predicted self-worth 1 year later, which in turn, predicted substance use, weapon carrying, and fighting in the 3rd year. Implications for the role of the secure base concept within the context of urban poverty are discussed.

  19. Prospective Relations among Low-Income African American Adolescents’ Maternal Attachment Security, Self-Worth, and Risk Behaviors

    PubMed Central

    Lockhart, Ginger; Phillips, Samantha; Bolland, Anneliese; Delgado, Melissa; Tietjen, Juliet; Bolland, John

    2017-01-01

    This study examined prospective mediating relations among mother-adolescent attachment security, self-worth, and risk behaviors, including substance use and violence, across ages 13–17 in a sample of 901 low-income African American adolescents. Path analyses revealed that self-worth was a significant mediator between attachment security and risk behaviors, such that earlier attachment security predicted self-worth 1 year later, which in turn, predicted substance use, weapon carrying, and fighting in the 3rd year. Implications for the role of the secure base concept within the context of urban poverty are discussed. PMID:28174548

  20. The 2011 Tohoku-oki Earthquake related to a strong velocity gradient within the Pacific plate

    NASA Astrophysics Data System (ADS)

    Matsubara, M.; Obara, K.

    2012-12-01

    1. Introduction We conduct seismic tomography using arrival time data picked by NIED Hi-net, including earthquakes off the coast, outside the seismic network around the source region of the 2011 Tohoku-oki Earthquake. For these offshore events, we use the centroid depth estimated from moment tensor inversion by NIED F-net. After the Tohoku-oki Earthquake we also used the centroid depth estimated from seismograms of high-sensitivity accelerometers operated by NIED with moment tensor inversion (Asano et al., 2011). 2. Data and method The target region, 20-48°N and 120-148°E, covers the Japanese Islands from Hokkaido to Okinawa. A total of manually picked 4,622,346 P-wave and 3,062,846 S-wave arrival times for 100,733 earthquakes recorded at 1,212 stations from October 2000 to August 2009 is available for use in the tomographic method. In the final iteration, we estimate the P-wave slowness at 458,234 nodes and the S-wave slowness at 347,037 nodes. The inversion reduces the root mean square of the P-wave traveltime residual from 0.455 s to 0.187 s and that of the S-wave data from 0.692 s to 0.228 s after eight iterations (Matsubara et al., 2011). After the Tohoku-oki earthquake, we also used arrival time data from many aftershocks determined by moment tensor inversion (Asano et al., 2011) composed of 1,089,228 P- and 593,191 S-wave arrival times from 4,384 events outside of the seismic network. Centroid depths are determined using a Green's function approach (Okada et al., 2004) such as in NIED F-net. For the events distant from the seismic network, the centroid depth is more reliable than that determined by NIED Hi-net, since there are no stations above the hypocenter. 3. Results and Discussion We determine the upper boundary of the Pacific plate based on the velocity structure and earthquake hypocentral distribution. The upper boundary of the low-V oceanic crust corresponds to the plate boundary where thrust earthquakes are expected to occur. Where we do not

  1. Zfp521 Is a Target Gene and Key Effector of Parathyroid Hormone-Related Peptide Signaling in Growth Plate Chondrocytes

    PubMed Central

    Correa, Diego; Hesse, Eric; Seriwatanachai, Dutmanee; Kiviranta, Riku; Saito, Hiroaki; Yamana, Kei; Neff, Lynn; Atfi, Azeddine; Coillard, Lucie; Sitara, Despina; Maeda, Yukiko; Warming, Soren; Jenkins, Nancy A.; Copeland, Neal G.; Horne, William C.; Lanske, Beate; Baron, Roland

    2010-01-01

    Summary In the growth plate, the interplay between Parathyroid Hormone-Related Peptide (PTHrP) and Indian Hedgehog (Ihh) signaling tightly regulates chondrocyte proliferation and differentiation during longitudinal bone growth. We found that PTHrP increases the expression of Zfp521, a zinc finger transcriptional co-regulator, in pre-hypertrophic chondrocytes. Mice with chondrocyte-targeted deletion of Zfp521 resembled PTHrP-/- and chondrocyte-specific PTHR1-/- mice, with decreased chondrocyte proliferation, early hypertrophic transition and reduced growth plate thickness. Deleting Zfp521 increased expression of Runx2 and Runx2 target genes, and decreased cyclin D1 and Bcl-2 expression while increasing caspase-3 activation and apoptosis. Zfp521 associated with Runx2 in chondrocytes, antagonizing its activity via an HDAC4-dependent mechanism. PTHrP failed to up-regulate cyclin D1 and to antagonize Runx2, Ihh and Collagen X expression when Zfp521 was absent. Thus, Zfp521 is an important PTHrP target gene that regulates growth plate chondrocyte proliferation and differentiation. PMID:20951345

  2. Analysis of batch-related influences on injection molding processes viewed in the context of electro plating quality demands

    NASA Astrophysics Data System (ADS)

    Siepmann, Jens P.; Wortberg, Johannes; Heinzler, Felix A.

    2016-03-01

    The injection molding process is mandatorily influenced by the viscosity of the material. By varying the material batch the viscosity of the polymer changes. For the process and part quality the initial conditions of the material in addition to the processing parameters define the process and product quality. A high percentage of technical polymers processed in injection molding is refined in a follow-up production step, for example electro plating. Processing optimized for electro plating often requires avoiding high shear stresses by using low injection speed and pressure conditions. Therefore differences in the material charges' viscosity occur especially in the quality related low shear rate area. These differences and quality related influences can be investigated by high detail rheological analysis and process simulation based on adapted material describing models. Differences in viscosity between batches can be detected by measurements with high-pressure-capillary-rheometers or oscillatory rheometers for low shear rates. A combination of both measurement techniques is possible by the Cox-Merz-Relation. The detected differences in the rheological behavior of both charges are summarized in two material behavior describing model approaches and added to the simulation. In this paper the results of processing-simulations with standard filling parameters are presented with two ABS charges. Part quality defining quantities such as temperature, pressure and shear stress are investigated and the influence of charge variations is pointed out with respect to electro plating quality demands. Furthermore, the results of simulations with a new quality related process control are presented and compared to the standard processing.

  3. The Effect of Message Framing on African American Women's Intention to Participate in Health-Related Research.

    PubMed

    Balls-Berry, Joyce E; Hayes, Sharonne; Parker, Monica; Halyard, Michele; Enders, Felicity; Albertie, Monica; Pinn, Vivian; Radecki Breitkopf, Carmen

    2016-05-01

    This study examined the effect of message framing on African American women's intention to participate in health-related research and actual registration in ResearchMatch (RM), a disease-neutral, national volunteer research registry. A community-engaged approach was used involving collaboration between an academic medical center and a volunteer service organization formed by professional women of color. A self-administered survey that contained an embedded message framing manipulation was distributed to more than 2,000 African American women attending the 2012 national assembly of The Links, Incorporated. A total of 391 surveys were completed (381 after exclusion: 187 containing the gain-framed message and 194 containing the loss-framed message). The majority (57%) of women expressed favorable intentions to participate in health-related research, and 21% subsequently enrolled in RM. The effect of message framing on intention was moderated by self-efficacy. There was no effect of message framing on RM registration; however, those with high self-efficacy were more than 2 times as likely as those with low self-efficacy to register as a potential study volunteer in RM (odds ratio = 2.62, 95% confidence interval [1.29, 5.33]). This investigation makes theoretical and practical contributions to the field of health communication and informs future strategies to meaningfully and effectively include women and minorities in health-related research.

  4. Phylogenetic relations of humans and African apes from DNA sequences in the Psi eta-globin region

    SciTech Connect

    Miyamoto, M.M.; Slightom, J.L.; Goodman, M.

    1987-10-16

    Sequences from the upstream and downstream flanking DNA regions of the Psi eta-globin locus in Pan troglodytes (common chimpanzee), Gorilla gorilla (gorilla), and Pongo pygmaeus (orangutan, the closest living relative to Homo, Pan, and Gorilla) provided further data for evaluating the phylogenetic relations of humans and African apes. These newly sequenced orthologs (an additional 4.9 kilobase pairs (kbp) for each species) were combined with published Psi eta-gene sequences and then compared to the same orthologous stretch (a continuous 7.1-kbp region) available for humans. Phylogenetic analysis of these nucleotide sequences by the parsimony method indicated (i) that human and chimpanzee are more closely related to each other than either is to gorilla and (ii) that the slowdown in the rate of sequence evolution evident in higher primates is especially pronounced in humans. These results indicate that features unique to African apes (but not to humans) are primitive and that even local molecular clocks should be applied with caution.

  5. Differential effects of stress and African ancestry on preterm birth and related traits among US born and immigrant Black mothers

    PubMed Central

    Tsai, Hui-Ju; Surkan, Pamela J.; Yu, Stella M.; Caruso, Deanna; Hong, Xiumei; Bartell, Tami R.; Wahl, Anastacia D.; Sampankanpanich, Claire; Reily, Anne; Zuckerman, Barry S.; Wang, Xiaobin

    2017-01-01

    Abstract Preterm birth (PTB, <37 weeks of gestation) is influenced by a wide range of environmental, genetic and psychosocial factors, and their interactions. However, the individual and joint effects of genetic factors and psychosocial stress on PTB have remained largely unexplored among U.S. born versus immigrant mothers. We studied 1121 African American women from the Boston Birth Cohort enrolled from 1998 to 2008. Regression-based analyses were performed to examine the individual and joint effects of genetic ancestry and stress (including lifetime stress [LS] and stress during pregnancy [PS]) on PTB and related traits among U.S. born and immigrant mothers. Significant associations between LS and PTB and related traits were found in the total study population and in immigrant mothers, including gestational age, birthweight, PTB, and spontaneous PTB; but no association was found in U.S. born mothers. Furthermore, significant joint associations of LS (or PS) and African ancestral proportion (AAP) on PTB were found in immigrant mothers, but not in U.S. born mothers. Although, overall, immigrant women had lower rates of PTB compared to U.S. born women, our study is one of the first to identify a subset of immigrant women could be at significantly increased risk of PTB and related outcomes if they have high AAP and are under high LS or PS. In light of the growing number of immigrant mothers in the U.S., our findings may have important clinical and public health implications. PMID:28151865

  6. Topographic form of the Coast Ranges of the Cascadia Margin in relation ot coastal uplift rates and plate subduction

    NASA Technical Reports Server (NTRS)

    Kelsey, Harvey M.; Engebretson, David C.; Mitchell, Clifton E.; Ticknor, Robert L.

    1994-01-01

    The Coast Ranges of the Cascadia margin are overriding the subducted Juan de Fuca/Gorda plate. We investigate the extent to which the latitudinal change in attributes related to the subduction process. These attributes include the varibale age of the subducted slab that underlies the Coast Ranges and average vertical crustal velocities of the western margin of the Coast Rnages for two markedly different time periods, the last 45 years and the last 100 kyr. These vertical crustal velocities are computed from the resurveying of highway bech marks and from the present elevation of shore platforms that have been uplifted in the late Quaternary, respectively. Topogarphy of the Coast Ranges is in part a function of the age and bouyancy of the underlying subducted plate. This is evident in the fact that the two highest topographic elements of the Coast Rnages, the Klamath Mountains and the Olympic Mountains, are underlain by youngest subducted oceanic crust. The subducted Blanco Fracture Zone in southernmost Oregon is responsible for an age discontinuity of subducted crust under the Klamath Mountains. The norhtern terminus of hte topographically higher Klamaths is offset to the north relative to the position of the underlying Blanco Fracture Zone, teh offset being in the direction of migration of the farcture zone, as dictated by relative plate motions. Vertical crustal velocities at the coast, derived from becnh mark surveys, are as much as an order of magnitude greater than vertical crustal velocities derived from uplifted shore platforms. This uplift rate discrepancy indicates that strain is accumulating on the plate margin, to be released during the next interplate earthquake. In a latitudinal sense, average Coast Rnage topography is relatively high where bench mark-derived, short-term vertical crustal velocities are highest. Becuase the shore platform vertical crustal velocities reflect longer-term, premanent uplift, we infer that a small percentage of the

  7. Characterization of African Human Retroviruses Related to HTLV-III/LAV

    DTIC Science & Technology

    1988-06-15

    DISTRIBUTION/AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION rOUNCLASSIFIED/JNLIMITED M SAME AS RPT. r3 DTiC ’,:;S Unclassified 22a. NAME OF...16 H1V-2-78/4.0 HIV-1 + + + + 19 REFERENCES (1) Kanki PJ, McLane ME, King NW Jr, Letvin NL, Hunt RD, Sehgal P, Daniel MD, Desrosiers RC, Essex M ...Kanki, P. J., Kurth, R. Becher, W., Dreesman, G., Mclane, M . F. Essex, M . Antibodies to simian T-lymnphotropic virus type III in African green monkeys

  8. The dissemination of 17D yellow fever vaccine in Africans in Kenya in relation to the interpretation of results of protection-test surveys

    PubMed Central

    Lumsden, W. H. R.

    1954-01-01

    The extent of dissemination of 17D yellow fever vaccine among the population of Kenya, especially among Africans, is estimated, largely from information in the records of the Kenya Medical Department. The total recorded vaccinations of Africans between 1941 and 1951 amount to about 379,000, representing 7.2% of the African population in 1948; it is, however, possible that the actual number of vaccinations is considerably higher. At Mombasa, 78,000 persons of races other than Africans were given routine inoculation over the same period. After a study of the economy of use of vaccine, the author discusses the protection-test surveys performed before 1951 and during that year in relation to the dissemination of vaccine. It is tentatively concluded that natural infection of man with yellow fever is rare in both Kenya and Tanganyika. PMID:13209303

  9. Propagation of SH waves in a piezoelectric/piezomagnetic plate: Effects of interfacial imperfection couplings and the related physical mechanisms

    NASA Astrophysics Data System (ADS)

    Wei, Hong-Xing; Li, Yong-Dong; Xiong, Tao; Guan, Yong

    2016-09-01

    The problem of dispersive SH wave in a piezoelectric/piezomagnetic plate that contains an imperfect interface is considered in the present work. An imperfection coupling model is adopted to describe the magnetic, electric and mechanical imperfections on the interface. A transcendental dispersion equation is derived and numerically solved to get the phase velocity. The validity of the numerical procedure is verified in a degenerated case. The effects of the coupled interfacial imperfections on the dispersion behavior of SH waves are discussed in detail and the related underlying physical mechanisms are explained.

  10. The Cultural Relevance of Mindfulness Meditation as a Health Intervention for African Americans: Implications for Reducing Stress-Related Health Disparities.

    PubMed

    Woods-Giscombé, Cheryl L; Gaylord, Susan A

    2014-09-01

    African Americans experience a disproportionate rate of stress-related health conditions compared to European Americans. Mindfulness meditation has been shown to be effective for managing stress and various stress-related health conditions. This study explored the cultural relevance of mindfulness meditation training for African Americans adults. Fifteen African American adults with past or current experience with mindfulness meditation training were interviewed. Participants felt that mindfulness meditation helped them with enhanced stress management, direct health improvement, and enhanced self-awareness and purposefulness. They felt that they would recommend it and that other African Americans would be open to the practice but suggested that its presentation may need to be adapted. They suggested emphasizing the health benefits, connecting it to familiar spiritual ideology and cultural practices, supplementing the reading material with African American writers, increasing communication (education, instructor availability, "buddy system," etc.), and including African Americans as instructors and participants. By implementing minor adaptations that enhance cultural relevance, mindfulness meditation can be a beneficial therapeutic intervention for this population.

  11. Relationship between Early Familial Influences and Personality Traits in Relation to Career Success Outcomes of African American Women

    ERIC Educational Resources Information Center

    Gardner, Keeba G.

    2010-01-01

    This study will examine the relationship between career success outcomes of African American women and early familial factors, as well as personality traits. Using a cross-sectional case-control design. the study will use participants who self-identified as African American with two African American parents. They will be randomly selected from a…

  12. AIDS-Related Stigmas and Safe-Sex Practices of African-American College Students: A Pilot Study.

    ERIC Educational Resources Information Center

    Chandler, Donald S., Jr.

    This study examined the safe-sex practices of African-American colleges students in light of culturally-specific beliefs that stigmatize Acquired Immune Deficiency Syndrome (AIDS) in the African-American community. A total of 21 self-selected, sexually-active African-American students (15 females and 6 males) aged 18-22 completed the AIDS…

  13. (Im)migrations, Relations, and Identities of African Peoples: Toward an Endarkened Transnational Feminist Praxis in Education

    ERIC Educational Resources Information Center

    Okpalaoka, Chinwe L.; Dillard, Cynthia B.

    2012-01-01

    This article focuses on the sense of what an "African" (American) identity could mean when viewed through the processes of migrations and fluid identities of contemporary African immigrant children as they interact with their African (Americans) peers in schools. The purpose of this article is to use data from a study of West African…

  14. Religious socialization in African American families: the relative influence of parents, grandparents, and siblings.

    PubMed

    Gutierrez, Ian A; Goodwin, Lucas J; Kirkinis, Katherine; Mattis, Jacqueline S

    2014-12-01

    The family is the principal context for religious and spiritual socialization. Although religion remains a central force in the lives of most African Americans, research has failed to explore the role and impact of family on religious socialization within this population. This study addresses that gap in the literature by (1) exploring adults' perceptions of the influence of their parents, grandparents, and siblings on their religious and spiritual lives, and (2) examining the extent to which those perceptions are associated with subjective religiosity, subjective spirituality, religious importance, and commitment to religious socialization among a community sample of urban-residing African American adults in the Midwest and Northeast (N = 319). Findings revealed that, on average, parents, grandparents, and siblings positively influenced adults' religious commitment and values. However, mothers had the greatest positive influence on these outcomes. Religious commitment and values were differentially associated with family members as a function of the generation and gender of the family member. The implications of these findings are discussed.

  15. The burden of natural and technological disaster-related mortality on gross domestic product (GDP) in the WHO African region.

    PubMed

    Kirigia, Joses M; Sambo, Luis G; Aldis, W; Mwabu, Germano M

    2002-01-01

    The WHO Africa region has the highest disaster mortality rate compared to the other five regions of the organization. Those deaths are hypothesized to have significantly negative effect on per capita gross domestic product (GDP). The objective of this study was to estimate the loss in GDP attributable to natural and technological disaster-related mortality in the WHO African Region. We estimated the impact of disaster-related mortality on GDP using double-log econometric model and cross-sectional data (from the UNDP and the World Bank publications) on 45 out of 46 countries in the WHO African Region. The coefficients for capital (K), educational enrolment (EN), life expectancy (LE) and exports (X) had a positive sign; while imports (M) and disaster mortality (DS) were found to impact negatively on GDP. The abovementioned explanatory variables were found to have statistically significant effect on GDP at 5% level in a t-distribution test. Disaster mortality of a single person was found to reduce GDP by US$0.018. We have demonstrated that disaster mortality has a significant negative effect on GDP. Thus, as policy-makers strive to increase GDP through capital investment, export promotion and increase in educational enrolment, they should always recall that investments in strengthening national capacity to mitigate the effects of national disasters expeditiously and effectively shall yield significant economic returns.

  16. Genomic Comparison of Indigenous African and Northern European Chickens Reveals Putative Mechanisms of Stress Tolerance Related to Environmental Selection Pressure.

    PubMed

    Fleming, Damarius S; Weigend, Steffen; Simianer, Henner; Weigend, Annett; Rothschild, Max; Schmidt, Carl; Ashwell, Christopher; Persia, Mike; Reecy, James; Lamont, Susan J

    2017-03-24

    Global climate change is increasing the magnitude of environmental stressors, such as temperature, pathogens, and drought that limit survivability and sustainability of livestock production. Poultry production and its expansion are dependent upon robust animals that are able to cope with stressors in multiple environments. Understanding the genetic strategies that indigenous, non-commercial breeds have evolved to survive in their environment could help to elucidate molecular mechanisms underlying biological traits of environmental adaptation. We examined poultry from diverse breeds and climates of Africa and Northern Europe for selection signatures that have allowed them to adapt to their indigenous environments. Selection signatures were studied using a combination of population genomic methods that employed FST , iHS, and runs of homozygosity procedures. All the analyses indicated differences in environment as a driver of selective pressure in both groups of populations. The analyses revealed unique differences in the genomic regions under selection pressure from the environment for each population. The African chickens showed stronger selection towards stress signaling and angiogenesis, while the Northern European chickens showed more selection pressure toward processes related to energy homeostasis. The results suggest that chromosomes 2 and 27 are the most diverged between populations and the most selected upon within the African (chromosome 27) and Northern European (chromosome 2) birds. Examination of the divergent populations have provided new insight into genes under possible selection related to tolerance of a population's indigenous environment that may be baselines for examining the genomic contribution to tolerance adaptions.

  17. Negative and positive peer influence: Relations to positive and negative behaviors for African American, European American, and Hispanic adolescents.

    PubMed

    Padilla-Walker, Laura M; Bean, Roy A

    2009-04-01

    The purpose of the current study was to examine adolescents' perceptions of negative and positive peer influence (i.e., indirect peer association and direct peer pressure) as they related to adolescent behavior. Regression analyses were conducted using a sample of African American, European American, and Hispanic adolescents (N=1659, M age=16.06, SD=1.10). The study found differences and similarities in relation to respondents' ethnicity vis-à-vis indirect peer association and adolescent behavior. Although few ethnic-based differences occurred as a function of indirect negative peer association, indirect positive peer association was not as consistently or as strongly related to behaviors for minority youth as it was for European American youth.

  18. Iberian plate kinematics: A jumping plate boundary between Eurasia and Africa

    USGS Publications Warehouse

    Srivastava, S.P.; Schouten, Hans; Roest, W.R.; Klitgord, Kim D.; Kovacs, L.C.; Verhoef, J.; Macnab, R.

    1990-01-01

    THE rotation of Iberia and its relation to the formation of the Pyrenees has been difficult to decipher because of the lack of detailed sea-floor spreading data, although several models have been proposed1-7. Here we use detailed aeromagnetic measurements from the sea floor offshore of the Grand Banks of Newfoundland to show that Iberia moved as part of the African plate from late Cretaceous to mid-Eocene time, with a plate boundary extending westward from the Bay of Biscay. When motion along this boundary ceased, a boundary linking extension in the King's Trough to compression along the Pyrenees came into existence. Finally, since the late Oligocene, Iberia has been part of the Eurasian plate, with the boundary between Eurasia and Africa situated along the Azores-Gibraltar fracture zone.

  19. Evaluation of Relative Sensitivity of SAW and Flexural Plate Wave Devices for Atmospheric Sensing

    NASA Technical Reports Server (NTRS)

    White, Richard M.; Black, Justin; Chen, Bryan

    1998-01-01

    The objective of this project is to evaluate the suitability of the ultrasonic flexural plate wave (FPW) device as the detector in a gas chromatograph (GC). Of particular interest is the detection of nitrous oxide (N2O). From experimental results we conclude analyte detection is achieved through two mechanisms: changes in gas density, and mass loading of the device membrane due to the sorption of gas molecules. Reducing the dead volume of the FPW chamber increased the FPW response. A comparison of the FPW response to that of the surface acoustic wave (SAW) detector provided with the GC (made by MSI, Microsensor Technologies, Inc.), shows that for unseparated N2O in N2, the FPW exhibits a sensitivity that is at least 550 times greater than that of the SAW device. A Porapak Q column was found to separate N2O from its carrier gas, N2 or He. With the Porapak Q column, a coated FPW detected 1 ppm N2O in N2 or He, with a response magnitude of 7 Hz. A coated SAW exhibited a response of 25 Hz to pure N2O. The minimal detectable N2O concentrations of the sensors were not evaluated.

  20. "She Told Them, Oh That Bitch Got AIDS": Experiences of Multilevel HIV/AIDS-Related Stigma Among African American Women Living with HIV/AIDS in the South.

    PubMed

    Fletcher, Faith; Ingram, Lucy Annang; Kerr, Jelani; Buchberg, Meredith; Bogdan-Lovis, Libby; Philpott-Jones, Sean

    2016-07-01

    African American women bear a disproportionate burden of HIV/AIDS in the United States. Although they constitute only 13% of the US population, African Americans account for nearly 65% of all new HIV infections among American women. In addition, this population suffers comparatively greater adverse health outcomes related to HIV status. African American women living with HIV in the South may be further burdened by HIV/AIDS stigma, which is comparatively more pronounced in this region. To further explore this burden, we used narrative data and the Social Ecological Model to explore how African American women living with HIV in the US South recount, conceptualize, and cope with HIV/AIDS stigma at interpersonal, community, and institutional levels. Our narrative analysis suggests that HIV-positive African American women living in the South are vulnerable to experiences of multilevel HIV stigma in various settings and contexts across multiple domains of life. Stigma subsequently complicated disclosure decisions and made it difficult for women to feel supported in particular social, professional and medical settings that are generally regarded as safe spaces for noninfected individuals. Findings suggest that the debilitating and compounded effect of multilevel HIV/AIDS stigma on HIV-positive African American women in the South warrants closer examination to tailor approaches that effectively address the unique needs of this population.

  1. Intervention induced changes on parenting practices, youth self-pride and sexual norms to reduce HIV-related behaviors among rural African American youths.

    PubMed

    Murry, Velma McBride; Berkel, Cady; Chen, Yi-Fu; Brody, Gene H; Gibbons, Frederick X; Gerrard, Meg

    2011-09-01

    AIDS is the leading killer of African Americans between the ages of 25 and 44, many of whom became infected when they were teenagers or young adults. The disparity in HIV infection rate among African Americans youth residing in rural Southern regions of the United States suggests that there is an urgent need to identify ways to promote early preventive intervention to reduce HIV-related risk behavior. The Strong African American Families (SAAF) program, a preventive intervention for rural African American parents and their 11-year-olds, was specially designed to deter early sexual onset and the initiation and escalation of alcohol and drug use among rural African American preadolescents. A clustered-randomized prevention trial was conducted, contrasting families who took part in SAAF with control families. The trial, which included 332 families, indicated that intervention-induced changes occurred in intervention-targeted parenting, which in turn facilitated changes in youths' internal protective processes and positive sexual norms. Long-term follow up assessments when youth were 17 years old revealed that intervention-induced changes in parenting practices mediated the effect of intervention-group influences on changes in the onset and escalation of risky sexual behaviors over 65 months through its positive influence on adolescents' self-pride and their sexual norms. The findings underscore the powerful effects of parenting practices among rural African American families that over time serve a protective role in reducing youth's risk behavior, including HIV vulnerable behaviors.

  2. Evolution of sprint speed in African savannah herbivores in relation to predation.

    PubMed

    Bro-Jørgensen, Jakob

    2013-11-01

    Predator-prey arms races are widely speculated to underlie fast speed in terrestrial mammals. However, due to lack of empirical testing, both the specificity of any evolutionary coupling between particular predator and prey species, and the relevance of alternative food-based hypotheses of speed evolution, remain obscure. Here I examine the ecological links between the sprint speed of African savannah herbivores, their vulnerability to predators, and their diet. I show that sprint speed is strongly predicted by the vulnerability of prey to their main predators; however, the direction of the link depends on the hunting style of the predator. Speed increases with vulnerability to pursuit predators, whereas vulnerability to ambush predators is associated with particularly slow speed. These findings suggest that differential vulnerability to specific predators can indeed drive interspecific variation in speed within prey communities, but that predator hunting style influences the intensity and consistency with which selection on speed is coupled between particular species.

  3. Violence exposure and health related risk among African American adolescent female detainees: A strategy for reducing recidivism.

    PubMed

    Woodson, Kamilah M; Hives, Courtney; Sanders-Phillips, Kathy

    2010-11-01

    Juvenile crime and violent victimization continue to be significant social problems (Fitzpatrick, Piko, Wright, & LaGory, 2005); in that, adolescents, females in particular, are likely to participate in health related risk behaviors as result of having been victimized or exposed to a violent environment. Specifically, abuse, neglect, sexual molestation, poverty, and witnessing violence are well known risk factors for the development of trauma-related psychopathology and poor outcomes relative to delinquency, drug and alcohol abuse, and HIV risk behaviors (Steiner, Garcia, & Matthews, 1997). HIV infection is a common public health concern disproportionally affecting adolescent African American female detainees. This unique population has a serious history of violence exposure, which subsequently tends to lead to engaging in risky sexual behaviors, mental health problems, and abusing substances. Also, as a result of little to no intervention, this population is recidivating at an alarming rate, a problem that may further exacerbate the expression of health-related risk behaviors among African American adolescent female detainees. The authors briefly describe a pilot program to be implemented in the juvenile justice system that is based on the Model of Accumulated Risk (Garbarino, 1996), Bronfenbrenner's Ecological Model (1994), and the Positive Youth Justice Model (Butts, Bazemore, & Meroe, 2009). The program proposes to reduce risky sexual behaviors, teach alternatives to abusing substances, treat mental health concerns, and reduce the rate of recidivism through "positive youth development", PYD (Butts, Bazemore, & Meroe, 2009). Tying elements of wraparound services and reeducation together, this program addresses salient concerns that may have an impact on an adolescent detainees' success following their release from prison in a holistic manner.

  4. Genetic variations in vitamin D-related pathways and breast cancer risk in African American women in the AMBER consortium.

    PubMed

    Yao, Song; Haddad, Stephen A; Hu, Qiang; Liu, Song; Lunetta, Kathryn L; Ruiz-Narvaez, Edward A; Hong, Chi-Chen; Zhu, Qianqian; Sucheston-Campbell, Lara; Cheng, Ting-Yuan David; Bensen, Jeannette T; Johnson, Candace S; Trump, Donald L; Haiman, Christopher A; Olshan, Andrew F; Palmer, Julie R; Ambrosone, Christine B

    2016-05-01

    Studies of genetic variations in vitamin D-related pathways and breast cancer risk have been conducted mostly in populations of European ancestry, and only sparsely in African Americans (AA), who are known for a high prevalence of vitamin D deficiency. We analyzed 24,445 germline variants in 63 genes from vitamin D-related pathways in the African American Breast Cancer Epidemiology and Risk (AMBER) consortium, including 3,663 breast cancer cases and 4,687 controls. Odds ratios (OR) were derived from logistic regression models for overall breast cancer, by estrogen receptor (ER) status (1,983 ER positive and 1,098 ER negative), and for case-only analyses of ER status. None of the three vitamin D-related pathways were associated with breast cancer risk overall or by ER status. Gene-level analyses identified associations with risk for several genes at a nominal p ≤ 0.05, particularly for ER- breast cancer, including rs4647707 in DDB2. In case-only analyses, vitamin D metabolism and signaling pathways were associated with ER- cancer (pathway-level p = 0.02), driven by a single gene CASR (gene-level p = 0.001). The top SNP in CASR was rs112594756 (p = 7 × 10(-5), gene-wide corrected p = 0.01), followed by a second signal from a nearby SNP rs6799828 (p = 1 × 10(-4), corrected p = 0.03). In summary, several variants in vitamin D pathways were associated with breast cancer risk in AA women. In addition, CASR may be related to tumor ER status, supporting a role of vitamin D or calcium in modifying breast cancer phenotypes.

  5. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  6. An Examination of the Factor Structure of the Index of Race-Related Stress among a Sample of African American Adolescents.

    ERIC Educational Resources Information Center

    Seaton, Eleanor K.

    2003-01-01

    Administered the Index of Race-Related Stress (IRRS), previously used with adults and college students, to urban African American high school students. Results provided evidence of validity for the IRRS, particularly for measuring race-related stress among adolescents. The measure required some modification, including deleting some items and…

  7. Racial and Ethnic-Related Stressors as Predictors of Perceived Stress and Academic Performance for African American Students at a Historically Black College and University

    ERIC Educational Resources Information Center

    Greer, Tawanda M.

    2008-01-01

    The purpose of this investigation was to determine whether racial and ethnic-related stressors were associated with overall levels of perceived stress and academic performance among African American students at a historically Black college and university (HBCU). Hierarchical regression analyses were used to test racial and ethnic-related stressors…

  8. An initial evaluation of a culturally adapted social problem-solving and relational aggression prevention program for urban African-American relationally aggressive girls.

    PubMed

    Leff, Stephen S; Gullan, Rebecca Lakin; Paskewich, Brooke S; Abdul-Kabir, Saburah; Jawad, Abbas F; Grossman, Michael; Munro, Melissa A; Power, Thomas J

    2009-01-01

    Recent research demonstrating that relational aggression is associated with peer relationship difficulties, internalizing and externalizing behaviors, social processing deficits, and possibly later mental health disorders among girls has emphasized the need to address the unique expression of aggression among females. Despite these findings, almost all aggression interventions have been directed toward physically aggressive boys. In the current article, the authors describe the acceptability and initial effectiveness of a culturally adapted social problem-solving/social skills intervention for inner-city 3rd- to 5th-grade urban, African American, relationally aggressive girls called the Friend to Friend Program. The authors partnered with youth, teachers, parents, and playground supervisors to design the program, and the current study presents preliminary data suggesting that the intervention is viewed as highly acceptable by participating girls and teachers. Further, the intervention appears to have promise for decreasing at-risk girls' levels of relationally and physically aggressive behaviors, hostile attributions, and loneliness.

  9. Relating the Stored Magnetic Energy of a Parallel-Plate Inductor to the Work of External Forces

    NASA Astrophysics Data System (ADS)

    Gauthier, N.

    2007-11-01

    Idealized models are often used in introductory physics courses. For one, such models involve simple mathematics, which is a definite plus since complex mathematical manipulations quickly become an obstacle rather than a tool for a beginner. Idealized models facilitate a student's understanding and grasp of a given physical phenomenon, yet they convey the essential elements of a sometimes intricate and abstract physical concept. It is thus worthwhile to use available models, or to develop new ones, for use in the introductory classroom. Early discussions of electric energy storage within the framework of the infinite parallel-plate capacitor model are an excellent case in point. In this case one can show, through relatively simple mathematical manipulations, that the work done by an external agent in order to increase the separation between the plates is equal to the corresponding change in the electrical energy of the system. The purpose of this paper is to show that a similar model can also be used to discuss magnetic energy storage based on a calculation of the work done by the external forces that act on the system, a subject that is greatly neglected at the introductory level. We examine this system next.

  10. West African monsoon decadal variability and surface-related forcings: second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II)

    NASA Astrophysics Data System (ADS)

    Xue, Yongkang; De Sales, Fernando; Lau, William K.-M.; Boone, Aaron; Kim, Kyu-Myong; Mechoso, Carlos R.; Wang, Guiling; Kucharski, Fred; Schiro, Kathleen; Hosaka, Masahiro; Li, Suosuo; Druyan, Leonard M.; Sanda, Ibrah Seidou; Thiaw, Wassila; Zeng, Ning; Comer, Ruth E.; Lim, Young-Kwon; Mahanama, Sarith; Song, Guoqiong; Gu, Yu; Hagos, Samson M.; Chin, Mian; Schubert, Siegfried; Dirmeyer, Paul; Ruby Leung, L.; Kalnay, Eugenia; Kitoh, Akio; Lu, Cheng-Hsuan; Mahowald, Natalie M.; Zhang, Zhengqiu

    2016-12-01

    The second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II) is designed to improve understanding of the possible roles and feedbacks of sea surface temperature (SST), land use land cover change (LULCC), and aerosols forcings in the Sahel climate system at seasonal to decadal scales. The project's strategy is to apply prescribed observationally based anomaly forcing, i.e., "idealized but realistic" forcing, in simulations by climate models. The goal is to assess these forcings' effects in producing/amplifying seasonal and decadal climate variability in the Sahel between the 1950s and the 1980s, which is selected to characterize the great drought period of the last century. This is the first multi-model experiment specifically designed to simultaneously evaluate such relative contributions. The WAMME II models have consistently demonstrated that SST forcing is a major contributor to the twentieth century Sahel drought. Under the influence of the maximum possible SST forcing, the ensemble mean of WAMME II models can produce up to 60 % of the precipitation difference during the period. The present paper also addresses the role of SSTs in triggering and maintaining the Sahel drought. In this regard, the consensus of WAMME II models is that both Indian and Pacific Ocean SSTs greatly contributed to the drought, with the former producing an anomalous displacement of the Intertropical Convergence Zone before the WAM onset, and the latter mainly contributes to the summer WAM drought. The WAMME II models also show that the impact of LULCC forcing on the Sahel climate system is weaker than that of SST forcing, but still of first order magnitude. According to the results, under LULCC forcing the ensemble mean of WAMME II models can produces about 40 % of the precipitation difference between the 1980s and the 1950s. The role of land surface processes in responding to and amplifying the drought is also identified. The results suggest that catastrophic

  11. Earth science: Plate motion and mantle plumes

    NASA Astrophysics Data System (ADS)

    Müller, R. Dietmar

    2011-07-01

    A model based on geophysical data from the Indian Ocean suggests that a mantle-plume head may once have coupled the motions of the African and Indian tectonic plates, and determined their respective speeds. See Article p.47

  12. Plant mineral concentrations related to foraging preferences of western lowland gorilla in Central African forest clearings.

    PubMed

    Metsio Sienne, Julia; Buchwald, Rainer; Wittemyer, George

    2014-12-01

    In the Central African rain forest, mineral resources essential to organisms are distributed heterogeneously. Forest clearings, locally known as bais, attract numerous species presumably due to the mineral richness of these sites, though understanding of the factors drawing species to bais remains speculative. Western lowland gorillas (Gorilla g. gorilla) selectively feed on particular plant species and parts within bais, but studies of such feeding preferences have focused on one site. Here, we compared concentrations of minerals and macronutrients from plants gorillas consumed and those they did not in 16 bais to gain inference regarding drivers of resource selection within bais and bai use. The availability of gorilla feeding plants varied between surveyed bais, with some consumed species occurring only at a few bais. Regardless of bai specific species composition, significantly higher concentrations of Na, K, and Ca were found in consumed plants, and other trace minerals were more common in consumed plants. In contrast, macronutrients appeared to play no major role in feeding plant selectivity with consumed species often having lower concentrations than non-consumed species. We found evidence for seasonal differences in Mg and Na concentrations, but the concentrations of other minerals in consumed plants were consistent across time. These findings provide insight to the drivers of bai visitation by gorillas. The high variation in species across bais may elicit use of multiple bais, but the general increased mineral composition of consumed species across bais suggests metabolic requirements may be met through consumption of a variety of species.

  13. Measuring health-related problem solving among African Americans with multiple chronic conditions: application of Rasch analysis.

    PubMed

    Fitzpatrick, Stephanie L; Hill-Briggs, Felicia

    2015-10-01

    Identification of patients with poor chronic disease self-management skills can facilitate treatment planning, determine effectiveness of interventions, and reduce disease complications. This paper describes the use of a Rasch model, the Rating Scale Model, to examine psychometric properties of the 50-item Health Problem-Solving Scale (HPSS) among 320 African American patients with high risk for cardiovascular disease. Items on the positive/effective HPSS subscales targeted patients at low, moderate, and high levels of positive/effective problem solving, whereas items on the negative/ineffective problem solving subscales mostly targeted those at moderate or high levels of ineffective problem solving. Validity was examined by correlating factor scores on the measure with clinical and behavioral measures. Items on the HPSS show promise in the ability to assess health-related problem solving among high risk patients. However, further revisions of the scale are needed to increase its usability and validity with large, diverse patient populations in the future.

  14. Jurassic silicic volcanism in the Transantarctic Mountains: Was it related to plate margin processes or to Ferrar magmatism?

    USGS Publications Warehouse

    Elliot, D.H.; Fleming, T.H.; Foland, K.A.; Fanning, C.M.

    2007-01-01

    Silicic volcanism in the Transantarctic Mountains, represented by rhyolitic tuff that mainly precedes emplacement of the Ferrar Large Igneous Province, is important in interpretation of the tectonic evolution of the Antarctic sector of Gondwana. Sr and Nd isotope data indicate that the tuffs are not directly related to Ferrar magmatism nor to melting of the underlying Ross orogen crust yet zircon gives a U-Pb age of 182.7±1.8 Ma, similar to the U/Pb age for the Ferrar. Distribution of the silicic tuffs along 1400 km of the Transantarctic Mountains suggests, alternatively, a relationship to the Gondwana plate margin. Although West Antarctica comprises Mesoproterozoic crustal terrains, few analyzed rocks are compatible isotopically with the Lower Jurassic tuffs. The source of the tuffs must lie in unexposed Early Jurassic magmatic centers in West Antarctica or an unexposed crustal terrain beneath the Transantarctic Mountains.

  15. Adherence to Traditionally Masculine Norms and Condom-Related Beliefs: Emphasis on African American and Hispanic Men

    PubMed Central

    Vincent, Wilson; Gordon, Derrick M.; Campbell, Christina; Ward, Nadia L.; Albritton, Tashuna; Kershaw, Trace

    2015-01-01

    Although studies have shown that adherence to traditional masculine norms (i.e., Status, Toughness, Antifemininity) affect men’s attitudes toward sexual health, there is little research on how men’s adherence to these norms affect them in the context of heterosexual, dyadic relationships. Among 296 young pregnant couples, we investigated the extent to which adherence to traditional masculine norms affected male and female partners’ own condom-related beliefs (i.e., condom self-efficacy, positive condom attitudes) and that of their partners. We tested an interdependence model using a dyadic-analytic approach to path analysis. We also tested for differences across gender and race-ethnicity (i.e., African American, Hispanic). Results showed that adherence to the Antifemininity and Toughness masculine norms predicted negative condom-related beliefs, whereas, overall, adherence to the Status norm predicted positive condom-related beliefs. Men’s and women’s adherence to traditional norms about masculinity were associated with their partner’s condom self-efficacy, and moderated associations based on gender and race-ethnicity were detected. In contrast, each dyad member’s traditional masculine norms were not associated with his or her partner’s positive condom attitudes. Taken together, findings indicated that the roles of traditional masculinity and condom-related beliefs in sexual health should be addressed within the context of relationships and associations between masculine norms and condom-related beliefs are not uniformly negative. PMID:26957949

  16. The central west Saharan dust hotspot and its relation to African easterly waves and extratropical disturbances

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Todd, Martin C.

    2010-05-01

    A vast, arid, and virtually uninhabited region covering eastern Mauritania and northern Mali appears in many satellite estimates of dust loading as the global maximum during boreal summer. Here the complex meteorological conditions that create this central western Sahara (CWS) dust hotspot are investigated on the basis of regression analyses and case study examples using a wide range of satellite analysis products (TOMS, OMI, MISR, SEVIRI). The results confirm the importance of African easterly waves (AEWs), previously hypothesized on the basis of case studies. The main ingredients to create this connection are: (I) Strengthened southerlies to the east of an AEW trough advect moist air into the southern Sahara. Daytime heating and orography trigger moist convection in this airmass. Strong evaporation in dry midlevel air generates extended cold pools and haboob dust storms. (II) Vertical mixing brings dust into the upper parts of the deep Saharan boundary layer, from where it can be advected back into the CWS region with the northerlies ahead of the next AEW trough. (III) If the associated surface vortex is strong enough, more dust emission occurs within or just upstream of the CWS. (IV) High-amplitude waves in the subtropics enhance the meridional flow associated with the AEW. Although there is a considerable case-to-case variability, it can be concluded that AEWs in concert with extratropical disturbances substantially contribute to the hotspot creation both through emission and the organization of transport. Disagreement between different satellite products and the presence of clouds complicate the analysis and underline the necessity for improved in-situ observations.

  17. A Bibliography of African Languages and Linguistics.

    ERIC Educational Resources Information Center

    Murphy, John D., Comp.; Goff, Harry, Comp.

    The present bibliography of African languages and linguistics includes not only works relating to the "Negro-African" languages, but also those dealing with the African varieties of Arabic, the Hamitic languages, Malagasy, Afrikaans, and various Creoles. (The greater part of the entries relate to the indigenous languages of the African continent…

  18. The association between disaster-related experiences and mental health outcomes among drug using African American Hurricane Katrina evacuees.

    PubMed

    Cepeda, Alice; Saint Onge, Jarron M; Kaplan, Charles; Valdez, Avelardo

    2010-12-01

    This article provides a detailed examination of the relationship between disaster-related experiences and mental health outcomes among a sample of drug using African American Hurricane Katrina evacuees. Face-to-face structured interviews were administered to Hurricane Katrina evacuees (n = 350) residing in voucher assisted apartment complexes in Houston, Texas (2006-2007). We use Ordinary Least Squares and logistic regression models to examine both the relevance of disaster-related experiences and the interactive relationships between disaster-related experiences and post-disaster mental health outcomes including psychological distress, severe depression, somatic symptoms, and posttraumatic stress disorder. Results indicate that disaster-related experiences including negative life changes, disaster exposure, post-disaster stressors, and resource loss, have unique, inverse relationships with mental health. While resource loss has the strongest inverse relationship with mental health, disaster exposure has a negative interactive effect on psychological distress and anxiety. Although highly vulnerable populations report low levels of mental health nearly 2 years following a disaster experience, there is a convergence in mental health outcomes with high levels of disaster experiences and disaster exposure that suggests mental resiliency.

  19. Genetic risk, parent-child relations, and antisocial phenotypes in a sample of African-American males.

    PubMed

    Beaver, Kevin M; Sak, Ashley; Vaske, Jamie; Nilsson, Jessica

    2010-01-30

    Gene x environment interactions have been found to be associated with the development of antisocial behaviors. The extant gene x environment research, however, has failed to measure directly the ways in which global measures of genetic risk may interact with a putative environmental risk factor. The current study addresses this gap in the literature and examines the interrelationships among a global measure of genetic risk based on five genetic polymorphisms, a measure of parent-child relations, and eight antisocial phenotypes. Analysis of African-American males (N = 145 to 159) drawn from the National Longitudinal Study of Adolescent Health (Add Health) revealed two broad findings. First, the genetic risk and parent-child relations scales were inconsistently related to the outcome variables. Second, genetic risk and parent-child relations interacted to predict variation in all of the eight antisocial phenotype measures. These findings point to the possibility that measures of genetic risk that are based on multiple polymorphisms can be employed to examine the gene x environmental basis to antisocial behavioral phenotypes.

  20. Relative impacts of insolation changes, meltwater fluxes and ice sheets on African and Asian monsoons during the Holocene

    NASA Astrophysics Data System (ADS)

    Marzin, Charline; Braconnot, Pascale; Kageyama, Masa

    2013-11-01

    In order to better understand the evolution of the Afro-Asian monsoon in the early Holocene, we investigate the impact on boreal summer monsoon characteristics of (1) a freshwater flux in the North Atlantic from the surrounding melting ice sheets and (2) a remnant ice sheet over North America and Europe. Sensitivity experiments run with the IPSL_CM4 model show that both the meltwater flux and the remnant ice sheets induce a cooling of similar amplitude of the North Atlantic leading to a southward shift of the Inter-Tropical Convergence Zone over the tropical Atlantic and to a reduction of the African monsoon. The two perturbations have different impacts in the Asian sector. The meltwater flux results in a weakening of the Indian monsoon and no change in the East Asian monsoon, whereas the remnant ice sheets induce a strengthening of the Indian monsoon and a strong weakening of the East Asian monsoon. Despite the similar coolings in the Atlantic Ocean, the ocean heat transport is reduced only in the meltwater flux experiment, which induces slight differences between the two experiments in the role of the surface latent heat flux in the tropical energetics. In the meltwater experiment, the southward shift of the subtropical jet acts to cool the upper atmosphere over the Tibetan Plateau and hence to weaken the Indian monsoon. In the ice sheet experiment this effect is overwhelmed by the changes in extratropical stationary waves induced by the ice sheets, which are associated with a larger cooling over the Eurasian continent than in the meltwater experiment. However these sensitivity experiments suggest that insolation is the dominant factor explaining the relative changes of the African, Indian and East Asian monsoons from the early to the mid-Holocene.

  1. European American and African American Mothers’ Emotion Socialization Practices Relate Differently to their Children’s Academic and Social-Emotional Competence

    PubMed Central

    Nelson, Jackie A.; Leerkes, Esther M.; Perry, Nicole B.; O’Brien, Marion; Calkins, Susan D.; Marcovitch, Stuart

    2012-01-01

    The current study examines whether the relation between mothers’ responses to their children’s negative emotions and teachers’ reports of children’s academic performance and social-emotional competence are similar or different for European American and African American families. Two hundred mothers (137 European American, 63 African American) reported on their responses to their 5-year-old children’s negative emotions and 150 kindergarten teachers reported on these children’s current academic standing and skillfulness with peers. Problem-focused responses to children’s negative emotions, which have traditionally been considered a supportive response, were positively associated with children’s school competence for European American children, but expressive encouragement, another response considered supportive, was negatively associated with children’s competence for African American children. The findings highlight the need to examine parental socialization practices from a culturally-specific lens. PMID:23914076

  2. Saying Grace: Praying over the Loss of African-American Religious and Food Culture (and How They Are Related)

    ERIC Educational Resources Information Center

    Hinton, Mary

    2008-01-01

    This article investigates the joint losses of food and religious culture in the African-American community, which has had a significant impact on the African-American community. Beginning with a historical perspective on the role of food in both a religious and cultural context, the article offers an analysis of why the dual losses have occurred,…

  3. The Experience of African Students Studying Nursing in the United States in Relation to Their Use of Critical Thinking

    ERIC Educational Resources Information Center

    Tyson, Donald Lee

    2012-01-01

    This qualitative study explores the critical thinking experiences of African nursing students enrolled in several universities in the U.S. Using a semi-structured interview approach, twelve African students discussed their experiences using and learning a western critical thinking approach, as well as described their educational experiences in…

  4. Age-Related Patterns in Social Networks among European Americans and African Americans: Implications for Socioemotional Selectivity across the Life Span.

    ERIC Educational Resources Information Center

    Fung, Helene H.; Carstensen, Laura L.; Lang, Frieder, R.

    2001-01-01

    Tests socioemotional selectivity theory among African Americans and European Americans. Older people reported as many close partners but fewer peripheral partners as their younger counterparts, thus confirming the theory. A greater percentage of close social partners in social networks related to lower levels of happiness among the young age group…

  5. Cultural, Sociofamilial, and Psychological Resources that Inhibit Psychological Distress in African Americans Exposed to Stressful Life Events and Race-Related Stress

    ERIC Educational Resources Information Center

    Utsey, Shawn O.; Giesbrecht, Norman; Hook, Joshua; Stanard, Pia M.

    2008-01-01

    This study tested a sociocultural model of stress and coping in a sample of 215 African Americans. Psychological resources (optimism, ego resilience) were modeled as a "nested self" (S. E. Hobfoll, 2001), supported by social resources (family adaptability and cohesion) and cultural resources (racial pride, religiosity). Race-related stress was a…

  6. Measurement characteristics of activity-related psychosocial measures in 8- to 10-year-old African-American girls in the Girls health Enrichment Multisite Study (GEMS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: This paper presents reliability and validity analyses of physical activity-related psychosocial questionnaires completed by 8- to 10-year-old African-American girls at baseline and follow-up assessments of pilot intervention studies in the Girls health Enrichment Multi-site Study (GEMS)....

  7. School Characteristics and Experiences of African American, Hispanic/Latino, and Native American Youth in Rural Communities: Relation to Educational Aspirations

    ERIC Educational Resources Information Center

    Irvin, Matthew J.; Byun, Soo-yong; Meece, Judith L.; Reed, Karla S.; Farmer, Thomas W.

    2016-01-01

    The primary purpose of this study was to examine differences in the school characteristics and experiences of African American, Hispanic/Latino, and Native American youth in rural high schools as well as their relation to educational aspirations. We also investigated the characteristics and experiences of students and their families given that…

  8. U.S. Church-Related Funding for Change in South Africa: An Analysis and an Inventory. South African Information Exchange Working Paper Number 7.

    ERIC Educational Resources Information Center

    Micou, Ann McKinstry

    A working paper on U.S. church-related funding for (or sponsorship of) South African programs is presented to guide support-seeking organizations in South Africa to appropriate resources and to inform interested parties outside South Africa about potential resources and ways in which they might cooperate or assist. Information is provided in two…

  9. A longitudinal examination of the relationship between sexual sensation seeking and STI-related risk factors among African American females.

    PubMed

    Voisin, Dexter R; Tan, Kevin; Diclemente, Ralph J

    2013-04-01

    Sexual sensation seeking has been correlated with STI-related risk factors in numerous cross sectional studies. However, no current studies have examined whether sexual sensation seeking is longitudinally related to a broad spectrum of STI-related factors such as consistent condom use, number of sexual partners, frequency of partner sexual communication, self-efficacy to refuse sex, and fear of condom negotiation. We explored these relationships over a 12-month period among a sample of 715 African American females attending three STI clinics in Georgia that were recruited into a larger randomized clinic intervention study. Utilizing A-CASI technology to assess all self-reported measures and employing general estimation equations while controlling for age, peer norms, school enrollment and employment, major results indicated that higher sexual sensation seeking predicted lower percent of condom use in the last 14 and 60 days, lower consistent condom use and a higher number of lifetime sexual partners. Additionally, higher sexual sensation seeking predicted lower partner sexual communication, diminished self-efficacy to refuse sex, and a higher fear of condom negotiation. Findings suggest that STI/HIV prevention/intervention programs should assess for and target sexual sensation seeking behaviors in such efforts.

  10. Plate Boundary Observatory and related networks: GPS data analysis methods and geodetic products

    NASA Astrophysics Data System (ADS)

    Herring, Thomas A.; Melbourne, Timothy I.; Murray, Mark H.; Floyd, Michael A.; Szeliga, Walter M.; King, Robert W.; Phillips, David A.; Puskas, Christine M.; Santillan, Marcelo; Wang, Lei

    2016-12-01

    The Geodesy Advancing Geosciences and EarthScope (GAGE) Facility Global Positioning System (GPS) Data Analysis Centers produce position time series, velocities, and other parameters for approximately 2000 continuously operating GPS receivers spanning a quadrant of Earth's surface encompassing the high Arctic, North America, and Caribbean. The purpose of this review is to document the methodology for generating station positions and their evolution over time and to describe the requisite trade-offs involved with combination of results. GAGE GPS analysis involves formal merging within a Kalman filter of two independent, loosely constrained solutions: one is based on precise point positioning produced with the GIPSY/OASIS software at Central Washington University and the other is a network solution based on phase and range double-differencing produced with the GAMIT software at New Mexico Institute of Mining and Technology. The primary products generated are the position time series that show motions relative to a North America reference frame and secular motions of the stations represented in the velocity field. The position time series themselves contain a multitude of signals in addition to the secular motions. Coseismic and postseismic signals, seasonal signals from hydrology, and transient events, some understood and others not yet fully explained, are all evident in the time series and ready for further analysis and interpretation. We explore the impact of analysis assumptions on the reference frame realization and on the final solutions, and we compare within the GAGE solutions and with others.

  11. Histological disorders related to the focal disappearance of the epiphyseal growth plate in rats induced by high dose of vitamin A.

    PubMed

    Soeta, S; Mori, R; Kodaka, T; Naito, Y; Taniguchi, K

    2000-03-01

    The histological disorders related to the focal disappearance of the epiphyseal growth plate were examined histochemically in the proximal tibia of rats administered a high dose of vitamin A. Animals were given 100,000 IU/100 g body weight/day of vitamin A for 5 days from 4 weeks after birth (VA rats) or given deionized water as control and sacrificed on Day 12 and 19 of the experiment. Tibiae were examined by immunohistochemistry for type I, II and X collagens, lectin-histochemistry for Helix pomatia and backscattered electron imaging. On Day 12, the abnormally developed calcified cartilage matrix was detected within the epiphyseal growth plate in VA rats. The uncalcified cartilage matrix contained type I collagen but lacked type II collagen. In addition, the eroded regions accompanied with numerous osteoclasts and osteoblasts were detected in the epiphyseal growth plate. On day 19, eroded regions penetrated the epiphyseal growth plate to result in its focal disappearances with the eroded surfaces entirely covered with bone tissue in VA rats. These findings suggested that the cartilage matrix of the epiphyseal growth plate was abnormally calcified and showed the phenotypes like bone matrix. The eroded regions of the epiphyseal growth plate seemed to be caused by the invasion of osteoclasts into the altered cartilage matrix and might develop to the focal disappearances by the modeling or remodeling due to action of osteoclasts and osteoblasts.

  12. Parathyroid hormone/parathyroid hormone-related protein receptor signaling is required for maintenance of the growth plate in postnatal life

    PubMed Central

    Hirai, Takao; Chagin, Andrei S.; Kobayashi, Tatsuya; Mackem, Susan; Kronenberg, Henry M.

    2011-01-01

    Parathyroid hormone (PTH)-related protein (PTHrP), regulated by Indian hedgehog and acting through the PTH/PTHrP receptor (PPR), is crucial for normal cartilage development. These observations suggest a possible role of PPR signaling in the postnatal growth plate; however, the role of PPR signaling in postnatal chondrocytes is unknown. In this study, we have generated tamoxifen-inducible and cartilage-specific PPR KO mice to evaluate the physiological role of PPR signaling in postnatal chondrocytes. We found that inactivation of the PPR in chondrocytes postnatally leads to accelerated differentiation of chondrocytes, followed by disappearance of the growth plate. We also observed an increase of TUNEL-positive cells and activities of caspase-3 and caspase-9 in the growth plate, along with a decrease in phosphorylation of Bad at Ser155 in postnatal PPR KO mice. Administration of a low-phosphate diet, which prevents apoptosis of chondrocytes, prevented the disappearance of the growth plate. Taken together, these observations suggest that the major consequences of PPR activation are similar in both the fetal and postnatal growth plates. Moreover, chondrocyte apoptosis through the activation of a mitochondrial pathway may be involved in the process of premature disappearance of the growth plate by postnatal inactivation of the PPR in chondrocytes. PMID:21173257

  13. Parathyroid hormone/parathyroid hormone-related protein receptor signaling is required for maintenance of the growth plate in postnatal life.

    PubMed

    Hirai, Takao; Chagin, Andrei S; Kobayashi, Tatsuya; Mackem, Susan; Kronenberg, Henry M

    2011-01-04

    Parathyroid hormone (PTH)-related protein (PTHrP), regulated by Indian hedgehog and acting through the PTH/PTHrP receptor (PPR), is crucial for normal cartilage development. These observations suggest a possible role of PPR signaling in the postnatal growth plate; however, the role of PPR signaling in postnatal chondrocytes is unknown. In this study, we have generated tamoxifen-inducible and cartilage-specific PPR KO mice to evaluate the physiological role of PPR signaling in postnatal chondrocytes. We found that inactivation of the PPR in chondrocytes postnatally leads to accelerated differentiation of chondrocytes, followed by disappearance of the growth plate. We also observed an increase of TUNEL-positive cells and activities of caspase-3 and caspase-9 in the growth plate, along with a decrease in phosphorylation of Bad at Ser155 in postnatal PPR KO mice. Administration of a low-phosphate diet, which prevents apoptosis of chondrocytes, prevented the disappearance of the growth plate. Taken together, these observations suggest that the major consequences of PPR activation are similar in both the fetal and postnatal growth plates. Moreover, chondrocyte apoptosis through the activation of a mitochondrial pathway may be involved in the process of premature disappearance of the growth plate by postnatal inactivation of the PPR in chondrocytes.

  14. Sublatitudinal Isotope Heterogeneity of The Atlantic and Adjacent Continents: A Relation To The Litospheric Plates and Superplums

    NASA Astrophysics Data System (ADS)

    Mironov, Yu. V.; Ryakhovsky, V. M.; Pustovoy, A. A.; Lapidus, I. V.

    Four Sr-Nd-Pb isotope sublatitudinal provinces are chosen in the Atlantic and on ad- jacent continents. They include mid-ocean ridges, oceanic rises and islands, as well as Late Mesozoic - Cenozoic continental rifts and traps. A modified Zindler-Hart "man- tle tetrahedron" (1986) have been used for rock systematics. Its major classification element alongside with known end-members (DM, HIMU, EM1, EM2) is any in- tratetrahedron component F ("focal") (Mironov et al., 2000; Rundquist et al., 2000; Ryakhovsky, 2000). It represents average characteristic of all known intratetrahedron components (FOZO, C, PREMA etc.), updated by methods of multidimensional statis- tics. Northern province includes Mid-Atlantic Ridge from a southern part of Reykjanes ridge up to 24S, numerous islands and rises, located at the same latitudes, Cameroon Line, African and European rifts, Aden and Red sea spreading centres, and also Co- mores in Indian ocean. The main composition dispersion of volcanics from withinplate oceanic and continental structures is determined by mixture of F and HIMU (rarely with admixture EM2). MORB within this area are characterized by stable admixture HIMU. Similar composition have the rocks in Bouvet-Antarctic province, within the limits of which the rises Spiss and Shona, the most southern part of Mid-Atlantic ridge, island Bouvet, an adjacent part of Southwest-Indian Ridge, and also traps and rifts on northern coast of Antarctic Continent are located. The Southern province lies in outlines of known Southern hemisphere DUPAL-anomaly (Hart, 1984). The with- inplate oceanic rocks (Gough, Tristan-da-Kunha, Walvis ridge, Rio Grande Plateau, Discovery) correspond to a mixture F + EM1 (sometimes F + EM1 + EM2) and are similar with traps of Southern America and Africa. Further to east this province is traced on islands and mid-ocean ridges in Indian ocean. MORB of Southern Atlantic and Indian ocean are enriched EM1. The Arctic province includes spreading ridges of

  15. Examining the Relational Processes of a Highly Successful Teacher of African American Children

    ERIC Educational Resources Information Center

    Cholewa, Blaire; Amatea, Ellen; West-Olatunji, Cirecie A.; Wright, Ashley

    2012-01-01

    Culturally responsive educational practices have arisen as effective means of increasing culturally diverse students' academic achievement and psychological well-being; however, the relational processes involved are not well understood. Using grounded theory, this study examines the relational processes of one culturally responsive teacher and her…

  16. Seismic structure related to the Philippine Sea plate subduction beneath the southwestern Nansei-Shoto (Ryukyu) Trench

    NASA Astrophysics Data System (ADS)

    Nishizawa, A.; Kaneda, K.; Oikawa, M.; Horiuchi, D.; Fujioka, Y.

    2013-12-01

    The northwestern part of the Philippine Sea plate (PSP) is subducting beneath the Nansei-Shoto (Ryukyu) Trench. Earthquakes larger than M8 have not been recorded instrumentally in the southwestern part of the Ryukyu Trench. However, there was a large tsunami killed around 12,000 people in 1771 and the position of the source area has not been established. The direction of the PSP subduction is almost perpendicular to the Ryukyu Trench to the northeast of 126.5 E and changes to oblique to the southwest. Seismicity varies along the trench axis and lower seismicity seems to correspond to the free-air gravity anomaly high region in the forearc at around 126 E. On the other hand, the Okinawa-Luzon fracture zone extending from southwest to northeast on the PSP subducts beneath Ryukyu Trench to the northeast of 126 E and seems to relate to the high gravity anomaly. We carried out seismic experiments to elucidate these inhomogeneous crustal structures along the southwestern part of the trench and provide valuable information on potential source areas for large earthquakes and/or tsunamis. We conducted five seismic lines across southwestern Ryukyu Trench region. Multichannel reflection seismic (MCS) data using 240 ch. and 3000 m long hydrophone streamer were collected for airgun shots at an interval of 50 m. We also deployed ocean bottom seismographs (OBSs) as a receiver at an average interval of 5 km along each line. A tri-gun cluster with a volume of 1,050 (350 * 3) cubic inches (17.2 liters) was used for the reflection surveys and a non-tuned airgun array with a volume of 6,000 (1500 * 4) cubic inches (98 liters) was shot at an interval of 200 m (90 sec) for the wide-angle seismic survey. Depth conversion from the MCS time section was carried out using the refraction results. In this paper, we present the seismic structure related to the PSP subduction in the forearc region of the Nansei-Shoto island arc. The subducting Okinawa-Luzon fracture zone was able to be clearly

  17. Tree foliar chemistry in an African savanna and its relation to life history strategies and environmental filters.

    PubMed

    Colgan, Matthew S; Martin, Roberta E; Baldeck, Claire A; Asner, Gregory P

    2015-01-01

    Understanding the relative importance of environment and life history strategies in determining leaf chemical traits remains a key objective of plant ecology. We assessed 20 foliar chemical properties among 12 African savanna woody plant species and their relation to environmental variables (hillslope position, precipitation, geology) and two functional traits (thorn type and seed dispersal mechanism). We found that combinations of six leaf chemical traits (lignin, hemi-cellulose, zinc, boron, magnesium, and manganese) predicted the species with 91% accuracy. Hillslope position, precipitation, and geology accounted for only 12% of the total variance in these six chemical traits. However, thorn type and seed dispersal mechanism accounted for 46% of variance in these chemical traits. The physically defended species had the highest concentrations of hemi-cellulose and boron. Species without physical defense had the highest lignin content if dispersed by vertebrates, but threefold lower lignin content if dispersed by wind. One of the most abundant woody species in southern Africa, Colophospermum mopane, was found to have the highest foliar concentrations of zinc, phosphorus, and δ(13)C, suggesting that zinc chelation may be used by this species to bind metallic toxins and increase uptake of soil phosphorus. Across all studied species, taxonomy and physical traits accounted for the majority of variability in leaf chemistry.

  18. Tree Foliar Chemistry in an African Savanna and Its Relation to Life History Strategies and Environmental Filters

    PubMed Central

    Colgan, Matthew S.; Martin, Roberta E.; Baldeck, Claire A.; Asner, Gregory P.

    2015-01-01

    Understanding the relative importance of environment and life history strategies in determining leaf chemical traits remains a key objective of plant ecology. We assessed 20 foliar chemical properties among 12 African savanna woody plant species and their relation to environmental variables (hillslope position, precipitation, geology) and two functional traits (thorn type and seed dispersal mechanism). We found that combinations of six leaf chemical traits (lignin, hemi-cellulose, zinc, boron, magnesium, and manganese) predicted the species with 91% accuracy. Hillslope position, precipitation, and geology accounted for only 12% of the total variance in these six chemical traits. However, thorn type and seed dispersal mechanism accounted for 46% of variance in these chemical traits. The physically defended species had the highest concentrations of hemi-cellulose and boron. Species without physical defense had the highest lignin content if dispersed by vertebrates, but threefold lower lignin content if dispersed by wind. One of the most abundant woody species in southern Africa, Colophospermum mopane, was found to have the highest foliar concentrations of zinc, phosphorus, and δ13C, suggesting that zinc chelation may be used by this species to bind metallic toxins and increase uptake of soil phosphorus. Across all studied species, taxonomy and physical traits accounted for the majority of variability in leaf chemistry. PMID:25993539

  19. A Comparative Assessment of Track Plates to Quantify Fine Scale Variations in the Relative Abundance of Norway Rats in Urban Slums.

    PubMed

    Hacker, Kathryn P; Minter, Amanda; Begon, Mike; Diggle, Peter J; Serrano, Soledad; Reis, Mitermayer G; Childs, James E; Ko, Albert I; Costa, Federico

    2016-06-01

    Norway rats (Rattus norvegicus) living in urban environments are a critical public health and economic problem, particularly in urban slums where residents are at a higher risk for rat borne diseases, yet convenient methods to quantitatively assess population sizes are lacking. We evaluated track plates as a method to determine rat distribution and relative abundance in a complex urban slum environment by correlating the presence and intensity of rat-specific marks on track plates with findings from rat infestation surveys and trapping of rats to population exhaustion. To integrate the zero-inflated track plate data we developed a two-component mixture model with one binary and one censored continuous component. Track plate mark-intensity was highly correlated with signs of rodent infestation (all coefficients between 0.61 and 0.79 and all p-values < 0.05). Moreover, the mean level of pre-trapping rat-mark intensity on plates was significantly associated with the number of rats captured subsequently (Odds ratio1.38; 95% CI 1.19-1.61) and declined significantly following trapping (Odds ratio 0.86; 95% CI 0.78-0.95). Track plates provided robust proxy measurements of rat abundance and distribution and detected rat presence even when populations appeared 'trapped out'. Tracking plates are relatively easy and inexpensive methods that can be used to intensively sample settings such as urban slums, where traditional trapping or mark-recapture studies are impossible to implement, and therefore the results can inform and assess the impact of targeted urban rodent control campaigns.

  20. Multi-decadal carbon and water relations of African tropical humid forests: a tree-ring stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Hufkens, K.; Beeckman, H.; de Haulleville, T.; Kearsley, E.; Toirambe, B.; Stoffelen, P.; Boeckx, P. F.

    2012-12-01

    Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree growth often displays itself as alternating pattern of visible rings due to the varying growth speed of the vascular cambium. Consequently, analysis of tree growth through tree-ring analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the width and density of growth rings reflect annual growth but their isotopic composition of 13C and 18O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-rings of 13C are influenced by fractionation through carboxylation and changes in stomatal conductance. Similarly, fractionation of 18O from soil water occurs at the leaf level through evapo-transipiration. As a consequence, δ18O values in tree cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, using both 13C and 18O stable isotopes might not only be valuable proxies of past climatic conditions but also serve as an important tool in understanding carbon and water relations within a forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree ring measurement of incremental growth and high resolution analysis of tree-core stable isotope (13C / 18O) composition at two functionally similar, but geographically dissimilar, tropical humid forests in DR Congo. A first site, the Luki man and the biosphere (MAB) reserve, is located in the western part of DR Congo influenced by a tropical wet and dry climate. A second site, the Yangambi MAB reserve is located in the north

  1. Multi-decadal carbon and water relations of African tropical humid forests: a tree-ring stable isotope analysis

    NASA Astrophysics Data System (ADS)

    Hufkens, Koen; Helle, Gerd; Beeckman, Hans; de Haulleville, Thales; Kearsley, Elizabeth; Boeckx, Pascal

    2013-04-01

    Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree growth often displays itself as alternating pattern of visible rings due to the seasonally varying growth speed of the vascular cambium. Consequently, analysis of tree growth through tree-ring analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the width and density of growth rings reflect annual growth but their isotopic composition of 13C/12C and 18O/16O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-rings of carbon are influenced by fractionation through carboxylation during photosynthesis and changes in leaf stomatal conductance. Similarly, fractionation of oxygen isotopes of soil water occurs at the leaf level through evapo-transipiration. As a consequence, 18O/16O (δ18O) values in wood cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, both C and O stable isotopes might not only be valuable as proxy data for past climatic conditions but they also serve as an important tool in understanding carbon and water relations within a tropical forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree ring measurement of incremental growth and high resolution analysis of tree-core stable isotope composition(δ13C , δ18O) at a tropical humid forests in the DR Congo. The Yangambi Man And Biosphere (MAB) reserve is located in the north-eastern part of DR Congo, with a distinct tropical rainforest climate. In addition to the tree-core data records and

  2. Relative risk of Alzheimer disease and age-at-onset distributions, based on APOE genotypes among elderly African Americans, caucasians, and hispanics in New York City

    SciTech Connect

    Tang, M.X.; Liu, X.H.; Stern, Y.

    1996-03-01

    Apolipoprotein-E {epsilon}4 (APOE-{epsilon}4) has been consistently associated with Alzheimer disease (AD) and may be responsible for an earlier age at onset. We have previously reported a diminished association between APOE-{epsilon}4 and AD in African Americans. Using a new method, which allows inclusion of censored information, we compared relative risks by APOE genotypes in an expanded collection of cases and controls from three ethnic groups in a New York community. The relative risk for AD associated with APOE-{epsilon}4 homozygosity was increased in all ethnic groups (African American relative risk [RR] = 3.0; 95% confidence interval [CI] = 1.5-5.9; Caucasian RR = 7.3, 95% CI = 2.5-21.6; and Hispanic RR = 2.5, 95% CI = 1.1-5.7), compared with those with APOE-{epsilon}3/{epsilon}3 genotypes. The risk was also increased for APOE-{epsilon}4 heterozygous Caucasians (RR = 2.9, 95% CI = 1.7-5.1) and Hispanics (RR = 1.6,95% CI = 1.1-2.3), but not for African Americans (RR = 0.6, 95% CI = 0.4-0.9). The age distribution of the proportion of Caucasians and Hispanics without AD was consistently lower for APOE-{epsilon}4 homozygous and APOE-{epsilon}4 heterozygous individuals than for those with other APOE genotypes. In African Americans this relationship was observed only in APOE-{epsilon}4 homozygotes. These results confirm that APOE genotypes influence the RR of AD in Caucasians and Hispanics. Differences in risk among APOE-{epsilon}4 heterozygote African Americans suggest that other genetic or environmental factors may modify the effect of APOE-{epsilon}4 in some populations. 58 refs., 3 figs., 4 tabs.

  3. Knowledge, Beliefs, and Behaviors: Examining Human Papillomavirus-Related Gender Differences among African American College Students

    ERIC Educational Resources Information Center

    Bynum, Shalanda A.; Brandt, Heather M.; Friedman, Daniela B.; Annang, Lucy; Tanner, Andrea

    2011-01-01

    Objective: Given recent approval for administration of a human papillomavirus (HPV) vaccine to men, it is important to assess the HPV-related perspectives of men and women. The purpose of this study was to examine gender differences in HPV knowledge, beliefs, and vaccine acceptance among college students attending 3 historically black…

  4. Relations of Transtheoretical Model Stage, Self-Efficacy, and Voluntary Physical Activity in African American Preadolescents

    ERIC Educational Resources Information Center

    Annesi, James J.; Faigenbaum, Avery D.; Westcott, Wayne L.

    2010-01-01

    The transtheoretical model (TTM; Prochaska, DiClemente, & Norcross, 1992) suggests that, at any point, an individual is in one of five stages-of-change related to adopting a behavior. People sequentially advance in stage but may also maintain or even regress, based on personal and environmental factors (Nigg, 2005). A classic study published in…

  5. HIV-Related Sexual Risk among African American Men Preceding Incarceration: Associations with Support from Significant Others, Family, and Friends.

    PubMed

    Coatsworth, Ashley M; Scheidell, Joy D; Wohl, David A; Whitehead, Nicole E; Golin, Carol E; Judon-Monk, Selena; Khan, Maria R

    2017-02-01

    We evaluated the association between social support received from significant others, family, and friends and HIV-related sexual risk behaviors among African American men involved in the criminal justice system. Project DISRUPT is a cohort study among African American men released from prison in North Carolina (N = 189). During the baseline (in-prison) survey, we assessed the amount of support men perceived they had received from significant others, family, and friends. We measured associations between low support from each source (

  6. Nodal Constraint, Shear Deformation and Continuity Effects Related to the Modeling of Debonding of Laminates, Using Plate Elements

    NASA Technical Reports Server (NTRS)

    Glaessgen, E. H.; Riddell, W. T.; Raju, I. S.

    2002-01-01

    The effects of several critical assumptions and parameters on the computation of strain energy release rates for delamination and debond configurations modeled with plate elements have been quantified. The method of calculation is based on the virtual crack closure technique (VCCT), and models of the upper and lower surface of the delamination or debond that use two-dimensional (2D) plate elements rather than three-dimensional (3D) solid elements. The major advantages of the plate element modeling technique are a smaller model size and simpler configurational modeling. Specific issues that are discussed include: constraint of translational degrees of freedom, rotational degrees of freedom or both in the neighborhood of the debond front, shear deformation assumptions; and continuity of material properties and section stiffness in the vicinity of the debond front. Where appropriate, the plate element analyses are compared with corresponding two-dimensional plane strain analyses.

  7. Helminth parasitism in two closely related South African rodents: abundance, prevalence, species richness and impinging factors.

    PubMed

    Spickett, Andrea; Junker, Kerstin; Krasnov, Boris R; Haukisalmi, Voitto; Matthee, Sonja

    2017-04-01

    We investigated patterns of helminth infection in two closely related rodents (social Rhabdomys pumilio occurring mainly in xeric habitats and solitary R. dilectus occurring mainly in mesic habitats) at 20 localities in different biomes of South Africa and asked if between-species differences were mainly caused by difference in sociality or difference in environmental conditions of their respective habitats. Helminths recovered from the gastrointestinal tract totalled 11 nematode and 5 cestode species from R. pumilio and 19 nematode and 7 cestode species from R. dilectus. In both hosts, mean abundance and prevalence of nematodes were higher compared to cestodes. Cestode infection as well as nematode abundance, species richness or prevalence did not differ between the two rodents. However, incidence of nematode infection was significantly higher in R. dilectus than in R. pumilio. Moreover, nematode numbers and species richness in infracommunities of R. pumilio inhabiting the relatively more xeric Karoo biome were significantly lower than in those inhabiting the relatively less xeric Fynbos biome. Although we could not unequivocally distinguish between effects of host sociality and environmental factors on the number of individuals and species of helminths in the two hosts, differences in the incidence of nematode infection between R. pumilio and R. dilectus as well as differences in the number of nematode individuals and species between R. pumilio from the Fynbos and the Karoo suggested the effect of environmental conditions on helminth infection to be more important than that of sociality.

  8. Multiple mantle upwellings in the transition zone beneath the northern East-African Rift system from relative P-wave travel-time tomography

    NASA Astrophysics Data System (ADS)

    Civiero, Chiara; Hammond, James O. S.; Goes, Saskia; Fishwick, Stewart; Ahmed, Abdulhakim; Ayele, Atalay; Doubre, Cecile; Goitom, Berhe; Keir, Derek; Kendall, J.-Michael; Leroy, Sylvie; Ogubazghi, Ghebrebrhan; Rümpker, Georg; Stuart, Graham W.

    2015-09-01

    Mantle plumes and consequent plate extension have been invoked as the likely cause of East African Rift volcanism. However, the nature of mantle upwelling is debated, with proposed configurations ranging from a single broad plume connected to the large low-shear-velocity province beneath Southern Africa, the so-called African Superplume, to multiple lower-mantle sources along the rift. We present a new P-wave travel-time tomography model below the northern East-African, Red Sea, and Gulf of Aden rifts and surrounding areas. Data are from stations that span an area from Madagascar to Saudi Arabia. The aperture of the integrated data set allows us to image structures of ˜100 km length-scale down to depths of 700-800 km beneath the study region. Our images provide evidence of two clusters of low-velocity structures consisting of features with diameter of 100-200 km that extend through the transition zone, the first beneath Afar and a second just west of the Main Ethiopian Rift, a region with off-rift volcanism. Considering seismic sensitivity to temperature, we interpret these features as upwellings with excess temperatures of 100 ± 50 K. The scale of the upwellings is smaller than expected for lower mantle plume sources. This, together with the change in pattern of the low-velocity anomalies across the base of the transition zone, suggests that ponding or flow of deep-plume material below the transition zone may be spawning these upper mantle upwellings. This article was corrected on 28 SEP 2015. See the end of the full text for details.

  9. Comparing HIV-related symbolic stigma in six African countries: social representations in young people’s narratives

    PubMed Central

    Winskell, Kate; Hill, Elizabeth; Obyerodhyambo, Oby

    2011-01-01

    HIV-related symbolic stigma arises from moralistic value judgements attached to people living with HIV and has negative consequences from both public health and human rights perspectives. Relatively little is known about cross-national variation in symbolic stigma. With the purpose of informing stigma reduction efforts within and across settings, we compared social representations of HIV in six African countries with estimated adult HIV prevalence rates ranging from 1 to 33%. Our study used a unique data source, namely a stratified random sample (n=586, ~5%) from 11,354 creative ideas contributed from six countries to a continent-wide HIV-related scriptwriting contest held between February and April2005. The narratives were written by equal numbers of males and females aged 10–24 in urban and rural areas of Swaziland, Namibia, Kenya, South-East Nigeria, Burkina Faso and Senegal. We combined three analytical approaches: descriptive statistics on certain quantifiable characteristics of the narratives, thematic data analysis, and a narrative-based approach. The association of HIV with outsiders (“othering”)and preoccupation with the circumstances of infection are more common in lower prevalence countries but vary substantially in tone depending on the sociocultural context. The highest proportion both of moralising narratives and of narratives with pessimistic outcomes come from South-East Nigeria and, to a lesser extent, from Kenya, countries with prevalence levels of 3.9 and 6.1% respectively, in which evangelical Christian movements, including Pentecostalism, have sizeable followings. The data provide a rare cross-cultural overview of symbolic stigma, identify country-specific needs, and point to strategies for future programming. Social representations from the highest prevalence countries, Swaziland and Namibia, and from lower prevalence Burkina Faso offer potential models for the framing of HIV in ways that serve to increase social proximity and counteract

  10. Sexually Transmitted Infection Related Stigma and Shame Among African American Male Youth: Implications for Testing Practices, Partner Notification, and Treatment

    PubMed Central

    Lippman, Sheri A.; Philip, Susan; Bernstein, Kyle; Neilands, Torsten B.; Lightfoot, Marguerita

    2014-01-01

    Abstract A self-administered, street intercept survey was conducted in order to examine the relation of stigma and shame associated with sexually transmitted infections (STI) to STI testing practices, partner notification, and partner-delivered treatment among young African American men (n=108) in a low-income, urban community in San Francisco with high STI burden. Multivariate logistic regression revealed that increasing STI-related stigma was significantly associated with a decreased odds of STI testing, such that every standard deviation increase in stigma score was associated with 0.62 decreased odds of having been tested (aOR: 0.62, 95% CI: 0.38–1.00), controlling for age. STI stigma was also significantly associated with a decreased willingness to notify non-main partners of an STI (aOR: 0.64 95% CI: 0.41–0.99). Participants with higher levels of stigma and shame were also significantly less likely to be willing to deliver STI medication to a partner (stigma aOR: 0.57, 95% CI: 0.37–0.88; shame aOR 0.53 95% CI: 0.34–0.83). Findings suggest that STI-related stigma and shame, common in this population, could undermine STI testing, treatment, and partner notification programs. The medical establishment, one of the institutional factors to have reinforced this culture of stigma, must aid efforts to reduce its effects through providing integrated services, reframing sexual health in campaigns, educating clients, and providing wider options to aid disclosure and partner notification practices. PMID:25133501

  11. A Structural Equation Model of HIV-Related Stigma, Racial Discrimination, Housing Insecurity and Wellbeing among African and Caribbean Black Women Living with HIV in Ontario, Canada

    PubMed Central

    Logie, Carmen H.; Jenkinson, Jesse I. R.; Earnshaw, Valerie; Tharao, Wangari; Loutfy, Mona R.

    2016-01-01

    African and Caribbean Black women in Canada have new HIV infection rates 7 times higher than their white counterparts. This overrepresentation is situated in structural contexts of inequities that result in social, economic and health disparities among African and Caribbean Black populations. Economic insecurity is a distal driver of HIV vulnerability, reducing access to HIV testing, prevention and care. Less is known about how economic insecurity indicators, such as housing security, continue to influence the lives of women living with HIV following HIV-positive diagnoses. The aim of this study was to test a conceptual model of the pathways linking HIV-related stigma, racial discrimination, housing insecurity, and wellbeing (depression, social support, self-rated health). We implemented a cross-sectional survey with African and Caribbean Black women living with HIV in 5 Ontario cities, and included 157 participants with complete data in the analyses. We conducted structural equation modeling using maximum likelihood estimation to evaluate the hypothesized conceptual model. One-fifth (22.5%; n = 39) of participants reported housing insecurity. As hypothesized, racial discrimination had significant direct effects on: HIV-related stigma, depression and social support, and an indirect effect on self-rated health via HIV-related stigma. HIV-related stigma and housing insecurity had direct effects on depression and social support, and HIV-related stigma had a direct effect on self-rated health. The model fit the data well: χ2 (45, n = 154) = 54.28, p = 0.387; CFI = 0.997; TLI = 0.996; RMSEA = 0.016. Findings highlight the need to address housing insecurity and intersecting forms of stigma and discrimination among African and Caribbean Black women living with HIV. Understanding the complex relationships between housing insecurity, HIV-related stigma, racial discrimination, and wellbeing can inform multi-level interventions to reduce stigma and enhance health. PMID

  12. African hot spot volcanism: small-scale convection in the upper mantle beneath cratons.

    PubMed

    King, S D; Ritsema, J

    2000-11-10

    Numerical models demonstrate that small-scale convection develops in the upper mantle beneath the transition of thick cratonic lithosphere and thin oceanic lithosphere. These models explain the location and geochemical characteristics of intraplate volcanos on the African and South American plates. They also explain the presence of relatively high seismic shear wave velocities (cold downwellings) in the mantle transition zone beneath the western margin of African cratons and the eastern margin of South American cratons. Small-scale, edge-driven convection is an alternative to plumes for explaining intraplate African and South American hot spot volcanism, and small-scale convection is consistent with mantle downwellings beneath the African and South American lithosphere.

  13. Morphology and kinematics of the rifted margin of West Antarctica in relation to separation from Zealandia and Bellingshausen plate motion

    NASA Astrophysics Data System (ADS)

    Wobbe, F.; Gohl, K.; Chambord, A.; Sutherland, R.

    2012-04-01

    The final breakup of Gondwana occurred during Late Cretaceous time as rifted continental crust of New Zealand separated from West Antarctica. Geophysical data acquired using R/V Polarstern constrain the structure and age of Antarctica's rifted oceanic margin. The Marie Byrd Land sector resembles a typical magma-poor margin with a narrow steep slope and a 145 km wide continent-ocean transition zone (COTZ). Our transect modelled from gravity and seismic reflection data indicates initial continental crust of thickness 24 km that was stretched 90 km. The Bellingshausen sector, east of the Antipodes Fault, is broad and complex with abundant evidence for later volcanism. The COTZ is ~670 km wide and substantial uncertainty remains as to the nature of crust within the COTZ. Extension estimates fall in the range of 106-304 km for this sector. Seafloor magnetic anomalies adjacent to the Marie Byrd Land sector at the longitude of the Pahemo Fracture Zone indicate a full-spreading rate during c33-c31 (80-68 Myr) of 60 mm/yr, increasing to 74 mm/yr at c27 (62 Myr), and then dropping to 22 mm/yr by c22 (50 Myr). Spreading rates were lower to the west. Extrapolation towards the continental margin indicates that initial oceanic crust formation was at ~c34y (84 Myr). The high extension rate of 30-60 mm/yr during the initial margin formation is consistent with the relatively sharp and symmetrical margin morphology, but subsequent motion of the Bellingshausen plate relative to Antarctica was slow and complex, and modified the rift morphology through migrating deformation and volcanic centres to create a broad and complex COTZ.

  14. Relative potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications. Issue study

    SciTech Connect

    Borden, C.S.; Schwartz, D.L.

    1984-12-31

    The purpose of this study is to assess the relative economic potentials of concentrating and two-axis tracking flat-plate photovoltaic arrays for central-station applications in the mid-1990's. Specific objectives of this study are to provide information on concentrator photovoltaic collector probabilistic price and efficiency levels to illustrate critical areas of R and D for concentrator cells and collectors, and to compare concentrator and flat-plate PV price and efficiency alternatives for several locations, based on their implied costs of energy. To deal with the uncertainties surrounding research and development activities in general, a probabilistic assessment of commercially achievable concentrator photovoltaic collector efficiencies and prices (at the factory loading dock) is performed. The results of this projection of concentrator photovoltaic technology are then compared with a previous flat-plate module price analysis (performed early in 1983). To focus this analysis on specific collector alternatives and their implied energy costs for different locations, similar two-axis tracking designs are assumed for both concentrator and flat-plate options. The results of this study provide the first comprehensive assessment of PV concentrator collector manufacturing costs in combination with those of flat-plate modules, both projected to their commercial potentials in the mid-1990's.

  15. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores.

    PubMed

    Dalerum, Fredrik; Miranda, Maria

    2016-02-25

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated.

  16. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores

    NASA Astrophysics Data System (ADS)

    Dalerum, Fredrik; Miranda, Maria

    2016-02-01

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated.

  17. Game auction prices are not related to biodiversity contributions of southern African ungulates and large carnivores

    PubMed Central

    Dalerum, Fredrik; Miranda, Maria

    2016-01-01

    There is an urgent need for human societies to become environmentally sustainable. Because public policy is largely driven by economic processes, quantifications of the relationship between market prices and environmental values can provide important information for developing strategies towards sustainability. Wildlife in southern Africa is often privately owned and traded at game auctions to be utilized for commercial purposes mostly related to tourism. This market offers an interesting opportunity to evaluate how market prices relate to biologically meaningful species characteristics. In this market, prices were not correlated with species contributions to either phylogenetic or functional diversity, and species contributions to phylogenetic or functional diversity did not influence the trends in prices over time for the past 20 years. Since this economic market did not seem to appreciate evolutionary or ecologically relevant characteristics, we question if the game tourism market may contribute towards biodiversity conservation in southern Africa. We suggest that market prices in general may have limited values as guides for directing conservation and environmental management. We further suggest that there is a need to evaluate what humans value in biological organisms, and how potentially necessary shifts in such values can be instigated. PMID:26911226

  18. Associations between Common Variants in Iron-Related Genes with Haematological Traits in Populations of African Ancestry

    PubMed Central

    Tanaka, Toshiko; Towers, G. Wayne; Verhoef, Hans; Veenemans, Jacobien; Talsma, Elise F.; Harryvan, Jan; Boekschoten, Mark V.; Feskens, Edith J.; Melse-Boonstra, Alida

    2016-01-01

    Background Large genome-wide association (GWA) studies of European ancestry individuals have identified multiple genetic variants influencing iron status. Studies on the generalizability of these associations to African ancestry populations have been limited. These studies are important given interethnic differences in iron status and the disproportionate burden of iron deficiency among African ancestry populations. Methods We tested the associations of 20 previously identified iron status-associated single nucleotide polymorphisms (SNPs) in 628 Kenyans, 609 Tanzanians, 608 South Africans and 228 African Americans. In each study, we examined the associations present between 20 SNPs with ferritin and haemoglobin, adjusting for age, sex and CRP levels. Results In the meta analysis including all 4 African ancestry cohorts, we replicated previously reported associations with lowered haemoglobin concentrations for rs2413450 (β = -0.19, P = 0.02) and rs4820268 (β = -0.16, P = 0.04) in TMPRSS6. An association with increased ferritin concentrations was also confirmed for rs1867504 in TF (β = 1.04, P = <0.0001) in the meta analysis including the African cohorts only. Conclusions In all meta analyses, we only replicated 4 of the 20 single nucleotide polymorphisms reported to be associated with iron status in large GWA studies of European ancestry individuals. While there is now evidence for the associations of a number of genetic variants with iron status in both European and African ancestry populations, the considerable lack of concordance highlights the importance of continued ancestry-specific studies to elucidate the genetic underpinnings of iron status in ethnically diverse populations. PMID:27332551

  19. Energy, protein, and zinc nutriture of rural African children in relation to some anthropometric indices

    SciTech Connect

    Ferguson, E.L.; Gibson, R.S.; Osei-Opare, F.; Opare-Obisaw, C.; Thompson, L.U. Univ. of Ghana, Legon Univ. of Toronto, Ontario )

    1991-03-11

    Heights, weights, arm circumferences, and triceps skinfold thicknesses of 66 Malawian and 148 Ghanaian preschool children were measured during 3 seasons. Their seasonal energy, protein, Ca, Zn, dietary fiber and phytate intakes were estimated from 3-day weighed records, using analyzed and literature food composition values. Seasonal hair Zn concentrations were analyzed by instrumental neutron activation analyses, The mean annual intakes for Malawian compared to Ghanaian children were higher for energy protein, and Zn. Cereals contributed a higher proportion of the total energy intake in the Malawian compared to the Ghanaian diets. A higher percentage of the Malawian children had height-for-age Z-scores below {minus}2SD, but a lower percentage had weight-for-height Z-scores below {minus}1SD compared to their Ghanaian counterparts. These differences may, in part be related to the high cereal intakes of the Malawian children.

  20. Integrated thermal and density modelling of the lithosphere across the Iberia-African plate boundary: the Gulf of Cadiz - Moroccan Atlas Geotransect

    NASA Astrophysics Data System (ADS)

    Zeyen, H.; Ayarza, P.; Fernàndez, M.; Rimi, A.

    2003-04-01

    The thermal and density structure of the lithosphere along a profile from the Gulf of Cadiz through the High Atlas to the Sahara is presented. The model is based on a numerical code that solves simultaneously the geopotential, lithostatic and heat transport equations integrating gravimetric, geoid, topographic and surface heat flow data, taking into account available geological and seismic constraints. Temperatures and densities are coupled by the thermal expansion, and the topography is considered to be in local isostatic equilibrium. The model presents an unusually thin lithosphere underneath the Atlas (60 to no more than 90 km) coinciding with areas of Neogene to Quaternary volcanism and relatively low P-wave velocities in the mantle. In contrast, the lithosphere underneath the Gulf of Cadiz thickens to 140-160 km depth. The relative amplitudes of geoid and gravity anomalies show that the high topography of the Atlas mountains cannot be produced only by crustal thickening. The lithospheric configuration, characterized by mantle thickening beneath the Gulf of Cadiz and thinning beneath the Atlas suggests a strong sub-lithospheric activity. Hence, westward drift of the lithospheric mantle in the Alboran region could be responsible for the observed mantle thickening and trigger sub-lithospheric erosion in the Atlas region.

  1. Association of APOL1 variants with mild kidney disease in the first-degree relatives of African American patients with non-diabetic end-stage renal disease.

    PubMed

    Freedman, Barry I; Langefeld, Carl D; Turner, Jolyn; Núñez, Marina; High, Kevin P; Spainhour, Mitzie; Hicks, Pamela J; Bowden, Donald W; Reeves-Daniel, Amber M; Murea, Mariana; Rocco, Michael V; Divers, Jasmin

    2012-10-01

    Familial aggregation of non-diabetic end-stage renal disease (ESRD) is found in African Americans and variants in the apolipoprotein L1 gene (APOL1) contribute to this risk. To detect genetic associations with milder forms of nephropathy in the high-risk families, analyses were performed using generalized estimating equations to assess relationships between kidney disease phenotypes and APOL1 variants in 786 relatives of 470 families. Adjusting for familial correlations, 23.1, 46.7, and 30.2% of genotyped relatives possessed two, one, or no APOL1 risk variants, respectively. Relatives with two compared with one or no risk variants had statistically indistinguishable median systolic blood pressure, urine albumin to creatinine ratio, estimated glomerular filtration rate (GFR; MDRD equation), and serum cystatin C levels. After adjusting for age, gender, age at ESRD in families, and African ancestry, significant associations were detected between APOL1 with overt proteinuria and estimated GFR (CKD-EPI equation), with a trend toward significance for quantitative albuminuria. Thus, relatives of African Americans with non-diabetic ESRD are enriched for APOL1 risk variants. After adjustment, two APOL1 risk variants weakly predict mild forms of kidney disease. Second hits appear necessary for the initiation of APOL1-associated nephropathy.

  2. Two jacalin-related lectins from seeds of the African breadfruit (Treculia africana L.).

    PubMed

    Shimokawa, Michiko; Nsimba-Lubaki, Shadrack Makuta; Hayashi, Namiko; Minami, Yuji; Yagi, Fumio; Hiemori, Keiko; Tateno, Hiroaki; Hirabayashi, Jun

    2014-01-01

    Two jacalin-related lectins (JRLs) were purified by mannose-agarose and melibiose-agarose from seeds of Treculia africana. One is galactose-recognizing JRL (gJRL), named T. africana agglutinin-G (TAA-G), and another one is mannose-recognizing JRL (mJRL), TAA-M. The yields of the two lectins from the seed flour were approximately 7.0 mg/g for gJRL and 7.2 mg/g for mJRL. The primary structure of TAA-G was determined by protein sequencing of lysyl endopeptic peptides and chymotryptic peptides. The sequence identity of TAA-G to other gJRLs was around 70%. Two-residue insertion was found around the sugar-binding sites, compared with the sequences of other gJRLs. Crystallographic studies on other gJRLs have shown that the primary sugar-binding site of gJRLs can accommodate Gal, GalNAc, and GalNAc residue of T-antigen (Galβ1-3GalNAcα-). However, hemagglutination inhibition and glycan array showed that TAA-G did not recognize GalNAc itself and T-antigen. TAA-G preferred melibiose and core 3 O-glycan.

  3. Pregnancy related breast diseases in a developing African country: Initial Sonographic Evaluation.

    PubMed

    Adeniji-Sofoluwe, Adenike Temitayo; Obajimi, Gbolahan Oladele; Obajimi, Millicent Olubunmi

    2015-01-01

    Benign diseases are more common than malignant diseases in pregnant and lactating women. Fibroadenomas are the most commonly identified benign breast tumour in pregnant and lactating women. Pregnancy related breast cancer is defined as breast cancer that occurs during pregnancy or within 1 year of delivery. Its incidence is estimated at 1 in 3000 to 1 in 10 000 pregnancies. Several reproductive factors like age at menarche, age at menopause, age at full-term pregnancy, parity, age at any birth and spacing of pregnancies, breast feeding, characteristics of the menstrual cycle, infertility, spontaneous and induced abortions, characteristics of the menstrual cycle and infertility are some of the factors that have been incriminated as risk factors for breast cancer. We sought to describe the predominant breast pattern, sonographic array of pregnancy related breast diseases in women referred to the breast imaging unit in the department of Radiology at the University College Hospital, Ibadan south west Nigeria. Socio-demographic characteristics in these women were also evaluated. Archived images were reviewed and documented and data was analysed with SPSS version 17 and presented with descriptives. In this descriptive study, we retrospectively retrieved the sonomammographic records of 21 women (pregnant or lactating) referred to and imaged in the department of radiology, University college hospital Ibadan, between 2006 and 2013. Diagnostic breast sonograms performed by MO and ATS; Consultant radiologists with 7-10 years' experience utilized a 7-10 MHz transducer of the General electric GE Logiq P5 machine for the scans. Twenty-one women with ages between 22-42 years (Mean 31.4 ± 5.4 SD) pregnant or lactating were referred to the radiology department for sonomammographic evaluation. Majority of the women were in the 3rd decade. Referral was mainly (11) by family Physicians from the general outpatient clinic, 5 were self-referred, 2 from radiotherapy department, 2 from

  4. Incidence and determinants of nevirapine and efavirenz-related skin rashes in West Africans: nevirapine's epitaph?

    PubMed

    Sarfo, Fred Stephen; Sarfo, Maame Anima; Norman, Betty; Phillips, Richard; Chadwick, David

    2014-01-01

    Non-nucleoside reverse transcriptase inhibitor (NNRTI) associated rash is common and frequently leads to discontinuation of NNRTIs. This study assessed the risk of developing rashes and discontinuing NNRTIs and associated factors in a large clinic in central Ghana. In this retrospective cohort study, clinical data were obtained in patients starting efavirenz or nevirapine between 2004-2010. Factors associated with rashes were explored using a multivariate Cox proportional hazards regression model. Of 3,999 patients who started NNRTI-based ART, 281 (7.0%) experienced at least one episode of NNRTI-related rash with an incidence of 2.63 events/100 person-years, occurring in 10.2% and 5.6% of patients taking nevirapine and efavirenz respectively. Most rashes (94%) were grade 1 or 2 and were reported a median of 2 months following initiation of ART. In multivariate analysis developing a rash was associated with nevirapine use (aHR 1.67, 95% CI 1.28-2.10), female gender (aHR of 1.39, 95% CI 1.01-1.92) and lower baseline CD4 counts (aHR 0.88, 95% CI 0.82-0.95 per 50 cells/mm³ increment). Patients with nevirapine-associated rash were 11 times more likely to discontinue treatment as patients with efavirenz-associated rash. In contrast to findings in other studies, NNRTI-associated rashes in Ghanaians appear more common in patients with lower baseline CD4 counts. Given the increased frequency of rashes with nevirapine and subsequent discontinuations in many patients, along with other treatment-limiting toxicities, this provides further impetus for the replacement of nevirapine by efavirenz as the first-line NNRTI treatment of choice in Africa.

  5. Incidence and Determinants of Nevirapine and Efavirenz-Related Skin Rashes in West Africans: Nevirapine's Epitaph?

    PubMed Central

    Sarfo, Fred Stephen; Sarfo, Maame Anima; Norman, Betty; Phillips, Richard; Chadwick, David

    2014-01-01

    Non-nucleoside reverse transcriptase inhibitor (NNRTI) associated rash is common and frequently leads to discontinuation of NNRTIs. This study assessed the risk of developing rashes and discontinuing NNRTIs and associated factors in a large clinic in central Ghana. In this retrospective cohort study, clinical data were obtained in patients starting efavirenz or nevirapine between 2004–2010. Factors associated with rashes were explored using a multivariate Cox proportional hazards regression model. Of 3,999 patients who started NNRTI-based ART, 281 (7.0%) experienced at least one episode of NNRTI-related rash with an incidence of 2.63 events/100 person-years, occurring in 10.2% and 5.6% of patients taking nevirapine and efavirenz respectively. Most rashes (94%) were grade 1 or 2 and were reported a median of 2 months following initiation of ART. In multivariate analysis developing a rash was associated with nevirapine use (aHR 1.67, 95% CI 1.28–2.10), female gender (aHR of 1.39, 95% CI 1.01–1.92) and lower baseline CD4 counts (aHR 0.88, 95% CI 0.82–0.95 per 50 cells/mm3 increment). Patients with nevirapine-associated rash were 11 times more likely to discontinue treatment as patients with efavirenz-associated rash. In contrast to findings in other studies, NNRTI-associated rashes in Ghanaians appear more common in patients with lower baseline CD4 counts. Given the increased frequency of rashes with nevirapine and subsequent discontinuations in many patients, along with other treatment-limiting toxicities, this provides further impetus for the replacement of nevirapine by efavirenz as the first-line NNRTI treatment of choice in Africa. PMID:24728406

  6. Work related musculoskeletal disorders and ergonomic stressors in the South African workforce.

    PubMed Central

    Schierhout, G H; Meyers, J E; Bridger, R S

    1995-01-01

    OBJECTIVES--The main objective of this study was to investigate exposure-response relations between adverse musculoskeletal outcomes and ergonomic exposure variables. METHODS--A cross sectional analytical study was conducted in 11 factories from seven sectors of manufacturing industry in South Africa. Exposure to workplace ergonomic stressors was assessed in factory floor jobs (n = 46) with a simple low technology observational model. Repetition, force, static posture, dynamic movement, and other job exposures were measured. Data of adverse musculoskeletal outcome and data on potential confounders and effect modifiers were obtained from subjects (n = 401) randomly sampled from each job category with a questionnaire given by interviewers. RESULTS--High prevalences of regional musculoskeletal pain were found with substantial variability between industries. Sex was the only individual risk factor (after adjustment for potential confounders and effect modifiers) that was significantly associated with regional pain. Ergonomic exposures in the workplace were significantly associated with musculoskeletal pain of the neck and shoulders odds ratio (OR) 5.38 (95% confidence interval (95% CI) 1.16 to 25.0) for repetition, and OR 3.91 (95% CI 1.11 to 13.7) for seated compared with standing work; pain of the wrists and hands OR 10.2 (95% CI 1.39 to 75.6) for high summed score of dynamic postures of the wrist). CONCLUSIONS--This study indicates good predictive ability to reduce ergonomic stress with the exposure model, simple surveillance methods, and educational programmes in the workplace. Further study on sampling strategies and refinement of dimensions of ergonomic stressors are needed. PMID:7697140

  7. Lithospheric structure under the western African-European plate boundary: A transect across the Atlas Mountains and the Gulf of Cadiz

    NASA Astrophysics Data System (ADS)

    Zeyen, Hermann; Ayarza, Puy; Fernã Ndez, Manel; Rimi, Abdelkrim

    2005-04-01

    We present a two-dimensional lithospheric thermal and density model along a transect running from the southwestern Iberian Peninsula to the northwestern Sahara. The main goal is to investigate the lithosphere structure underneath the Gulf of Cadiz and the Atlas Mountains. The model is based on the assumption of topography in local isostatic equilibrium and is constrained by surface heat flow, gravity anomalies, geoid, and topography data. The crustal structure has been constrained by seismic and geological data where available. Mantle density is supposed to vary linearly with temperature, providing the link between thermal and density-related data. The lithospheric thickness varies strongly along the profile, going from near 100 km under the Iberian Peninsula to at least 160-190 km under the Gulf of Cadiz and the Gharb foreland basin in Morocco and to 70 km underneath the Atlas Mountains, coinciding with a region of Neogene volcanism. The thickening of the lithosphere is interpreted as a SW trending lithospheric slab extending from the western Betics to the Gulf of Cadiz and the Gharb Basin, whereas the thin lithosphere underneath the Atlas may be interpreted as plume-like asthenospheric upwelling similar to those observed in the west European Alpine foreland or as a side effect of a slab penetrating the less viscous asthenosphere.

  8. Relation of plasma calcium to total protein and albumin in African grey (Psittacus erithacus) and Amazon (Amazona spp.) parrots.

    PubMed

    Lumeij, J T

    1990-10-01

    A significant correlation was found between total calcium and albumin concentration in the plasma of 70 African grey parrots (r=0.37; P<0.05). A correlation formula for plasma calcium concentration in the African grey parrot was derived on the basis of the concentration of albumin: Adjusted Ca (mmol/1) = Ca (mmol/1) - 0.015 Albumin (g/1) + 0.4. About 14% of the variability in calcium was attributable to the change in the concentration of plasma albumin concentration (R2=0.137). The correlation between calcium and total protein in African greys and between calcium and albumin and calcium and total protein in Amazons was not significant.

  9. Knowledge, Attitudes and Practices Related to African Swine Fever Within Smallholder Pig Production in Northern Uganda.

    PubMed

    Chenais, E; Boqvist, S; Sternberg-Lewerin, S; Emanuelson, U; Ouma, E; Dione, M; Aliro, T; Crafoord, F; Masembe, C; Ståhl, K

    2017-02-01

    Uganda is a low-income country with the largest pig population in East Africa. Pig keeping has a large potential, commercially and as a tool for poverty reduction, but African swine fever (ASF) is a major hurdle for development of the sector. The objective of this study was to evaluate knowledge, attitudes and practices related to ASF in the smallholder pig production value chain in northern Uganda. The study included three separate series of participatory rural appraisals (PRA), comprising purposively selected farmers and other actors in the pig production value chain. In the PRAs, various participatory epidemiology tools were used. A total of 49 PRAs and 574 participants, representing 64 different villages, were included. The results indicate that participants were well aware of the clinical signs of ASF, routes for disease spread and measures for disease control. However, awareness of the control measures did not guarantee their implementation. A majority of middlemen and butchers acknowledged having sold live pigs, carcasses or pork they believed infected with ASF. Outbreaks of ASF had a strong negative impact on participants' socio-economic status with loss of revenue and reversal into more severe poverty. In conclusion, lack of knowledge is not what is driving the continuous circulation of ASF virus in this setting. To control ASF and reduce its impact, initiatives that stimulate changes in management are needed. Because the behaviour of all actors in the value chain is largely influenced by the deep rural poverty in the region, this needs to be combined with efforts to reduce rural poverty.

  10. Expression of melatonin receptors in triple negative breast cancer (TNBC) in African American and Caucasian women: relation to survival.

    PubMed

    Oprea-Ilies, Gabriela; Haus, Erhard; Sackett-Lundeen, Linda; Liu, Yuan; McLendon, Lauren; Busch, Robert; Adams, Amy; Cohen, Cynthia

    2013-02-01

    In the normal rodent breast, the pineal hormone melatonin controls the development of ductal and alveolar tissue. Melatonin counteracts tumor occurrence and tumor cell progression in vivo and in vitro in animal and human breast cancer cell cultures. It acts predominantly through its melatonin MT1 receptor. Our aim was to investigate the presence or absence of the MT1 melatonin receptor in the aggressive triple negative group of human breast carcinoma (TNBC) and its possible relationship to the course of the disease. A total of 167 patients with a ER-, PR-, Her-2/neu- phenotype in which tissue for receptor studies was available were examined. The MT1 receptor immunostain was evaluated semiquantitatively as staining intensity (0, 1, 2, 3), percentage of stained cells and the weighted index (WI) (staining intensity times percentage of stained cells). A score of WI < 60 was regarded as "negative". There was a striking difference in incidence of MT1 positivity and staining intensity between carcinomas in African American (AA) and Caucasian (C) women. The AA showed a higher incidence of MT1 negative tumors (41/84 = 48.8 % in AA, 6/51 = 11.8 % in C) and a lower average WI. MT1 positivity in TNBC was associated with a lower stage and a smaller tumor size at time of diagnosis. In multivariable survival analysis, MT1 negative TNBC in all cases regardless of race showed a significantly higher hazard ratio for disease progression, shorter progression free survival, and disease-related death, and shorter OS. This was especially pronounced in the AA group but did not reach statistical significance in the smaller group of C alone. These results suggest that melatonin or a melatonin receptor agonist may be useful biologic additions in the treatment of some forms of TNBC, especially in AA who generally show a more aggressive course of their disease.

  11. Contextual factors influencing health-related quality of life in African American and Latina breast cancer survivors

    PubMed Central

    Miller, Aria M.; Ashing, Kimlin Tam; Modeste, Naomi N.; Herring, R. Patti; Sealy, Diadrey-Anne T.

    2015-01-01

    Purpose This study explored the relationships between systemic and individual-level contextual factors and health-related quality of life (HRQOL) in a cohort of African American and Latina breast cancer survivors (BCS). Methods Baseline questionnaire data of 320 BCS who participated in a HRQOL psycho-educational intervention were abstracted from the parent study. Hierarchical regression analysis tested the independent effects of contextual factors on HRQOL. Results HRQOL was higher in BCS who: were diagnosed at related factors accounted for 14 % of the variance in HRQOL (F[6, 274]= 7.25, p<0.001). The socio-cultural context (i.e., ethnicity, life stress, perceived social support) explained 20% of the variance in HRQOL (FΔ[3, 271]=27.32, p<0.001). The health care system context contributed an additional 8 % to explaining HRQOL (FΔ[1, 270]=34.88, p<0.001). Health status and behavioral factors accounted for 18 % of the variance (FΔ[4, 266]=29.55, p<0.001). The full model explained 59 % of the variance in HRQOL (F[14, 266]=27.76, p<0.001). Conclusions HRQOL in ethnic minority BCS is multifaceted and is significantly influenced by cancer-related, socio-cultural, health care system, health status, and behavioral contextual factors. Therefore, survivorship research and practice must address broad multi-level domains to achieve equitable and optimal breast cancer outcomes. Implications for cancer survivors To enhance HRQOL, survivors must be provided the know-how and support to maintain healthy lifestyle and self-management practices. Advocates must engage the care team to consider systemic factors, including life stress and community resources, to be more patient-centered. PMID:25576214

  12. African American Single Mothers: Understanding Their Lives and Families. Sage Series on Race and Ethnic Relations, Volume 10.

    ERIC Educational Resources Information Center

    Dickerson, Bette J.

    Past research on African American single mothers and their families has been conducted using conventional paradigms based upon models of the dominant culture. This practice has resulted in the creation of stereotypes and misconceptions about "the Black family." In this collection of original work by an interdisciplinary group of…

  13. Gender Mainstreaming in a South African Provincial Education Department: A Transformative Shift or Technical Fix for Oppressive Gender Relations?

    ERIC Educational Resources Information Center

    Karlsson, Jenni

    2010-01-01

    Although some gender activists and analysts question the efficacy of gender mainstreaming to take forward women's demands, the South African government has pursued the strategy within a number of government departments including the Department of Education. This article explores how the strategy is being implemented in one provincial education…

  14. The Relations of Stressful Events and Nonacademic Future Expectations in African American Adolescents: Gender Differences in Parental Monitoring

    ERIC Educational Resources Information Center

    Cunningham, Michael; Mars, Dustin E.; Burns, Lateela J.

    2012-01-01

    Urban African American high school students (N = 206) completed a study to examine gender differences in parental monitoring and the effect on the relationship between exposure to stressful life events and nonacademic future expectations. Participant's ages range from 13 to 18 (M = 15.78, SD = 1.19). Participants reported high exposure to…

  15. Polymorphisms of Estrogen Metabolism-Related Genes and Prostate Cancer Risk in Two Populations of African Ancestry

    PubMed Central

    Emeville, Elise; Ferdinand, Séverine; Punga, Augustin; Lufuma, Simon; Blanchet, Pascal; Romana, Marc; Multigner, Luc

    2016-01-01

    Background Estrogens are thought to play a critical role in prostate carcinogenesis. It has been suggested that polymorphisms of genes encoding enzymes involved in estrogen metabolism are risk factors for prostate cancer. However, few studies have been performed on populations of African ancestry, which are known to have a high risk of prostate cancer. Objective We investigated whether functional polymorphisms of CYP17, CYP19, CYP1B1, COMT and UGT1A1 affected the risk of prostate cancer in two different populations of African ancestry. Methods In Guadeloupe (French West Indies), we compared 498 prostate cancer patients and 565 control subjects. In Kinshasa (Democratic Republic of Congo), 162 prostate cancer patients were compared with 144 controls. Gene polymorphisms were determined by the SNaPshot technique or short tandem repeat PCR analysis. Logistic regression was used to estimate adjusted odds ratios (OR) and 95% confidence intervals (CI). Results The AA genotype and the A allele of rs4680 (COMT) appeared to be inversely associated with the risk of prostate cancer in adjusted models for both Afro-Caribbean and native African men. For the A allele, a significant inverse association was observed among cases with low-grade Gleason scores and localized clinical stage, in both populations. Conclusions These preliminary results support the hypothesis that polymorphisms of genes encoding enzymes involved in estrogen metabolism may modulate the risk of prostate cancer in populations of African ancestry. PMID:27074016

  16. Cultural Learning Context as It Relates to Efficacy and the Mathematics Performance of African-American Middle School Students

    ERIC Educational Resources Information Center

    Burrell, Jennifer O.

    2012-01-01

    Nearly 20 years of empirical work has demonstrated that cultural-asset focused learning environments can improve the academic performance of African-American students. One example is communal learning context, which shifts students' motivational primacy from the individual to the social group. Considering the critical role of efficacy beliefs in…

  17. Social and cultural factors are related to perceived colorectal cancer screening benefits and intentions in African Americans.

    PubMed

    Purnell, Jason Q; Katz, Mira L; Andersen, Barbara L; Palesh, Oxana; Figueroa-Moseley, Colmar; Jean-Pierre, Pascal; Bennett, Nancy

    2010-02-01

    Models that explain preventive behaviors, such as colorectal cancer (CRC) screening, do not account for social and cultural factors relevant to African Americans. This exploratory study examined the relationship between socio-cultural factors (e.g., traditional acculturative strategy, group-based medical mistrust, physician ethnicity, and group-level perceptions of susceptibility) and perceived benefits, perceived barriers, and CRC screening intentions among African Americans (N = 198; Age: M = 59.7, SD = 9.9; 65% female; 44% household income $50,000+). Hierarchical multiple regression was used to test the following models with perceived benefits, perceived barriers, and screening intentions as the outcomes: (a) traditional acculturative strategy x medical mistrust; (b) physician's ethnicity x medical mistrust; (c) group susceptibility x medical mistrust; and (d) group susceptibility x traditional acculturative strategy. Results revealed that perceiving high group susceptibility while being both more culturally traditional and less mistrustful was associated with more perception of screening benefits. Greater intention to be screened was associated with perceiving high group susceptibility while having a more traditional cultural orientation and low levels of mistrust in those with African American physicians. These results suggest that it may be beneficial to include these social and cultural factors in behavioral interventions to increase CRC screening among African Americans.

  18. Maternal Control and Sensitivity, Child Gender, and Maternal Education in Relation to Children's Behavioral Outcomes in African American Families

    ERIC Educational Resources Information Center

    Tamis-LeMonda, Catherine S.; Briggs, Rahil D.; McClowry, Sandra G.; Snow, David L.

    2009-01-01

    This study examined relationships between mother-child interactions and children's behaviors in 119 urban African American mothers and their 6-7 year old children. Interactions during a cooking task and a follow-up child clean-up task were videotaped. Principal components analyses of behaviors during the cooking task yielded two factors in mothers…

  19. The Effects of Stakeholder Disconnect Related to the Achievement of Classified African American Males in Middle School

    ERIC Educational Resources Information Center

    Wilson, Roy T.

    2014-01-01

    This study examined the disconnect between child study teams, teachers, principals and parents in the monitoring of IEP's and effective implementation of interventions needed to move African American males from special education placements to mainstream classes. In addition, stakeholder attitudes, perceptions, opinions, and beliefs were examined…

  20. Sharing Information about Peer Relations: Parent and Adolescent Opinions and Behaviors in Hmong and African American Families

    ERIC Educational Resources Information Center

    Brown, B. Bradford; Bakken, Jeremy P.; Nguyen, Jacqueline; Von Bank, Heather G.

    2007-01-01

    Despite sharing similar attitudes regarding the information about peers that parents have a right to know, the strategies African American and Hmong families use to seek or censor information about peers diverge because of ethnic differences in emphasis on trust, nurturing autonomy, respect for parental authority, and maintaining cultural…

  1. Kinematics and dynamics of the northern North American Cordillera: deformation related to plate convergence, flat-slab subduction, and gravitational potential energy

    NASA Astrophysics Data System (ADS)

    Finzel, E.; Flesch, L. M.; Ridgway, K. D.

    2009-12-01

    We use finite element models to investigate the deformational driving forces in Alaska and northwestern Canada as they relate to flat-slab subduction, tectonic extrusion, and existing block models. First, long-term velocity and strain rate fields are quantified using continuous spline functions to interpolate between observed strain rate data inferred from: 1) select GPS sites interpreted to represent the long-term signal of deformation, 2) plate and microplate motion models, 3) ridge spreading rates, 4) seismicity, and 5) Quaternary fault slip rates. Our calculated fault slip rates indicate that ~82% of the mostly dextral motion between the Pacific and North American plates is accommodated along the Queen Charlotte fault system to the east, whereas the Aleutian Megathrust accommodates ~60% of the oblique convergence between the Pacific and North American plates to the west. The highest strain rate magnitudes are located along plate margin faults and above the region of flat-slab subduction of the Yakutat microplate. Furthermore, results from our best-fit kinematic model suggest that the interaction between the Pacific, North American, and Bering plates may be the dominant driver controlling southwestward rotation of the velocity field in southern Alaska. Whereas this outcome cannot conclusively rule out the possibility of tectonic extrusion in the study area, it does not support it either. Next, we calculate the two primary sources of deviatoric stress responsible for driving deformation in Alaska, namely deviatoric stresses associated with gravitational potential energy (GPE) variations in the lithosphere (buoyancy forces) and relative plate motions and basal tractions (boundary forces). We find the affects of incorporating, versus excluding, a subducting slab in GPE calculations for this region to be minimal. Deviatoric stress magnitudes associated with the vertically averaged GPE within a 100-km-thick lithosphere are on the order of 5-10 MPa, whereas magnitudes

  2. Adiposity and hyperglycaemia in pregnancy and related health outcomes in European ethnic minorities of Asian and African origin: a review

    PubMed Central

    Jenum, Anne Karen; Sommer, Christine; Sletner, Line; Mørkrid, Kjersti; Bærug, Anne; Mosdøl, Annhild

    2013-01-01

    Background Ethnic minorities in Europe have high susceptibility to type 2 diabetes (T2DM) and, in some groups, also cardiovascular disease (CVD). Pregnancy can be considered a stress test that predicts future morbidity patterns in women and that affects future health of the child. Objective To review ethnic differences in: 1) adiposity, hyperglycaemia, and pre-eclampsia during pregnancy; 2) future risk in the mother of obesity, T2DM and CVD; and 3) prenatal development and possible influences of maternal obesity, hyperglycaemia, and pre-eclampsia on offspring's future disease risk, as relevant for ethnic minorities in Europe of Asian and African origin. Design Literature review. Results Maternal health among ethnic minorities is still sparsely documented. Higher pre-pregnant body mass index (BMI) is found in women of African and Middle Eastern descent, and lower BMI in women from East and South Asia compared with women from the majority population. Within study populations, risk of gestational diabetes mellitus (GDM) is considerably higher in many minority groups, particularly South Asians, than in the majority population. This increased risk is apparent at lower BMI and younger ages. Women of African origin have higher risk of pre-eclampsia. A GDM pregnancy implies approximately seven-fold higher risk of T2DM than normal pregnancies, and both GDM and pre-eclampsia increase later risk of CVD. Asian neonates have lower birth weights, and mostly also African neonates. This may translate into increased risks of later obesity, T2DM, and CVD. Foetal overgrowth can promote the same conditions. Breastfeeding represents a possible strategy to reduce risk of T2DM in both the mother and the child. Conclusions Ethnic minority women in Europe with Asian and African origin and their offspring seem to be at increased risk of T2DM and CVD, both currently and in the future. Pregnancy is an important window of opportunity for short and long-term disease prevention. PMID:23467680

  3. Lung cancer in relation to exposure to silica dust, silicosis and uranium production in South African gold miners

    PubMed Central

    Hnizdo, E.; Murray, J.; Klempman, S.

    1997-01-01

    BACKGROUND: A nested case-control study for lung cancer was performed on a cohort of 2260 South African gold miners in whom an association between exposure to silica dust and risk of lung cancer was previously reported. The objective was to investigate an expanded set of risk factors and also cancer cell type. METHODS: The 78 cases of lung cancer found during the follow up period from 1970 to 1986 were matched with 386 controls. Risk of lung cancer was related to smoking, exposure to silica dust, incidence of silicosis, and uranium production and the uranium content of the mine ore. RESULTS: The risk of lung cancer was associated with tobacco smoking, cumulative dust exposure, duration of underground mining, and with silicosis. The best predictive model included pack years of cigarette consumption (adjusted relative risk (RR) = 1.0 for < 6.5 pack years, 3.5 (95% confidence interval (CI) 0.7 to 16.8) for 6.5-20 pack years, 5.7 (95% CI 1.3 to 25.8) for 21-30 pack years, and 13.2 (95% CI 3.1 to 56.2) for more than 30 pack years) and silicosis (RR = 2.45 (95% CI 1.2 to 5.2)). No association was found with uranium production. The lung tumour cell type distribution was 40.3% small cell carcinoma, 38.8% squamous cell, 16.4% adenocarcinoma, and 4.5% large cell carcinoma. Small and large cell cancer combined were associated with exposure to dust. CONCLUSIONS: The results cannot be interpreted definitively in terms of causal association. Possible interpretations are: (1) subjects with high dust exposure who develop silicosis are at increased risk of lung cancer; (2) high levels of exposure to silica dust on its own is important in the pathogenesis of lung cancer and silicosis is coincidental; and (3) high levels of silica dust exposure may be a surrogate for the exposure to radon daughters. 


 PMID:9093345

  4. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  5. Plate kinematics of the Afro-Arabian Rift System with emphasis on the Afar Depression, Ethiopia

    NASA Astrophysics Data System (ADS)

    Bottenberg, Helen Carrie

    This work utilizes the Four-Dimensional Plates (4DPlates) software, and Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine plate-scale, regional-scale and local-scale kinematics of the Afro-Arabian Rift System with emphasis on the Afar Depression in Ethiopia. First, the 4DPlates is used to restore the Red Sea, the Gulf of Aden, the Afar Depression and the Main Ethiopian Rift to development of a new model that adopts two poles of rotation for Arabia. Second, the 4DPlates is used to model regional-scale and local-scale kinematics within the Afar Depression. Most plate reconstruction models of the Afro-Arabian Rift System relies on considering the Afar Depression as a typical rift-rift-rift triple junction where the Arabian, Somali and Nubian (African) plates are separating by the Red Sea, the Gulf of Aden and the Main Ethiopian Rift suggesting the presence of "sharp and rigid" plate boundaries. However, at the regional-scale the Afar kinematics are more complex due to stepping of the Red Sea propagator and the Gulf of Aden propagator onto Afar as well as the presence of the Danakil, Ali Sabieh and East Central Block "micro-plates". This study incorporates the motion of these micro-plates into the regional-scale model and defined the plate boundary between the Arabian and the African plates within Afar as likely a diffused zone of extensional strain within the East Central Block. Third, DInSAR technology is used to create ascending and descending differential interferograms from the Envisat Advanced Synthetic Aperture Radar (ASAR) C-Band data for the East Central Block to image active crustal deformation related to extensional tectonics and volcanism. Results of the DInSAR study indicate no strong strain localization but rather a diffused pattern of deformation across the entire East Central Block.

  6. A new visualization of the motion of the Indian Plate in the Cenozoic

    NASA Astrophysics Data System (ADS)

    Holmes, J. J.; Stegman, D. R.

    2011-12-01

    90 million years ago the Indian Plate detached from the ancient supercontinent Gondwana and diverged away from the Antarctic and African plates in a northwest-wards direction. Evidence from magnetic anomalies and paleomagnetic data shows that between 67 and 49 million years ago spreading rates increased the Indian plate to anomalously rapid velocities, with a peak of nearly 200 mm/yr relative to the African plate. Cande and Stegman (2011) have shown new evidence that the Indian Plate acceleration was caused by a push force originating from the Reunion mantle plume. Two notable slowdowns occurred during that time period: a sharp reduction in velocity at 63 million years ago, and another more gradual reduction from 52 to 45 million years ago. The first slowdown coincides with rapidly dwindling flood basalt eruptions caused by the plume head of the Reunion mantle plume. The second slowdown is thought to be due to collision with either the Eurasian continent or a now extinct intermediate plate that may have contained an island arc. We are motivated to create a new visual model using new data and considering the Reunion plume as a driving force. Using the GPlates tectonics modeling software and rotation data developed by the EarthBytes Project we reconstruct the trajectory to develop a velocity vector model of the Indian plate. We use these tools to explore alternative plate reconstructions, such as one that includes a collision between India and a hypothetical intraoceanic arc beginning at 52 Ma (Ali and Aitchison, 2008) to help explain the reduction in plate velocity over the 7 million year span during the second slowdown.

  7. Study of phytoplankton group distribution in the NW African upwelling system and its relation with hydrographical parameters

    NASA Astrophysics Data System (ADS)

    Vega Moreno, Daura; Llerandi-García, C.; Pérez-Marrero, J.; Rueda, M. J.; Llinás, O.

    2010-05-01

    Phytoplankton is one important factor in biogeochemical cycles in the ocean, controlling partly the carbon cycle in the ocean. The CO2 captured by phytoplankton in shallow waters is transported to deeper layers in the ocean (Anderson, 2005). This only happens when microplankton or nanoplankton is formed due to their bigger size contributes their sinking to deeper layers. In the case of picoplankton the carbon is recycled in the same zone where is produced. The type of phytoplankton predominant can vary according to hydrographical and chemical properties present (Jeffrey et al., 2005). Pigment speciation can provide valuable ecological information in the form of classification of phytoplanktonic biomass in different groups (chlorophyta, diatoms, dinoflagellates, coccolithophorids or silicoflagellates) organized in different sizes: microphytoplankton (20-200 µm), nanophytoplankton (2-20 µm) and picophytoplankton (0.2-2 µm). There are different data processing methodologies for obtaining these classifications, one of the most accepted is the procedure taken by NASA (Hooker et al., 2005) developed by Vidussi et al. (2001), and also the use of CHEMTAX program (Mackey, 1996). It was studied pigment composition of phytoplankton and several physical and chemical properties, focused in the Northwestern African Upwelling area, including Senegal area, Mauritanian and Cape Blanc area and Morroco area. Pigment composition was analyzed by high pressure liquid chromatography and determined in different samples in the studied area, with this composition it was obtained phytoplankton classification, according to their size and to the different phytoplankton groups. These results have been related with marine biogeochemical factors presents in studied zone. References: - Anderson, T. Plankton functional type modelling: running before we can walk? Journal of Plankton Research, 2005, 27, 1073-7081 - Hooker, S.; Heukelem, L.; Thomas, C.; Claustre, H.; Ras, J.; Barlow, R.; Sessions

  8. Slab dragging and the recent geodynamic evolution of the western Mediterranean plate boundary region

    NASA Astrophysics Data System (ADS)

    Spakman, Wim; Chertova, Maria V.; van den Berg, Arie P.; Thieulot, Cedric; van Hinsbergen, Douwe J. J.

    2016-04-01

    The Tortonian-Present geodynamic evolution of the plate boundary between North Africa and Iberia is characterized by first-order enigmas. This concerns, e.g., the diffuse tectonic activity of the plate boundary; the crustal thickening below the Rif; the closing of the northern Moroccan marine gateways prior to the Messinian Salinity Crisis; crustal extension of the central to eastern Betics; the origin and sense of motion of the large left-lateral Trans Alboran Shear Zone (TASZ) and Eastern Betic Shear Zone (EBSZ); and lithosphere delamination of the North African continental edge. Many explanations have been given for each of these seemingly disparate tectonic features, which invariably have been addressed in the plate tectonic context of the NW-SE relative plate convergence between the major plates since the Tortonian, mostly independently from each other. Usually there is no clear role for the subducted slab underlying the region, except for presumed rollback, either to SW or to the W, depending on the type of observations that require explanation. Here we integrate the dynamic role of the slab with the NW-SE relative plate convergence by 3-D numerical modelling of the slab evolution constrained by absolute plate motions (Chertova et al., JGR,2014 & Gcubed 2014). By combining observations and predictions from seismology, geology, and geodesy, with our numerical 3-D slab-mantle dynamics modelling, we developed a new and promising geodynamic framework that provides explanations of all noted tectonic enigmas in a coherent and connected way. From the Tortonian until today, we propose that mantle-resisted slab dragging combines with the NW-SE plate convergence across the (largely) unbroken plate boundary to drive the crustal deformation of the region. Slab dragging is the lateral transport, pushing or pulling, of slab through the mantle by the absolute motion of the subducting plate (Chertova et al., Gcubed, 2014). Because the slab is connected to both the Iberian

  9. Charts relating the compressive buckling stress of longitudinally supported plates to the effective deflectional and rotational stiffness of the supports

    NASA Technical Reports Server (NTRS)

    Anderson, Roger A; Semonian, Joseph W

    1954-01-01

    A stability analysis is made of a long flat rectangular plate subjected to a uniform longitudinal compressive stress and supported along its longitudinal edges and along one or more longitudinal lines by elastic line supports. The elastic supports possess deflectional and rotational stiffness. Such configuration is an idealization of the compression cover skin and internal structure of a wing and tail surfaces. The results of the analysis are presented in the form of charts in which the buckling-stress coefficient is plotted against the buckle length of the plate for a wide range of support stiffnesses. The charts make possible the determination of the compressive buckling stress of plates supported by members whose stiffness may or may not be defined by elementary beam bending and twisting theory but yet whose effective restraint is amenable to evaluation. The deflectional and rotational stiffness provided by longitudinal stiffeners and full-depth webs is discussed and numerical examples are given to illustrate the application of the charts to the design of wing structures.

  10. Assessment of pain and analgesic use in African American cancer patients: factors related to adherence to analgesics.

    PubMed

    Rhee, Young O; Kim, Eugenia; Kim, Bryant

    2012-12-01

    This study describes pain experience, analgesic use and barriers to pain control in African American cancer patients (N = 116). The overall adherence rate of analgesics was 46%. Constipation and nausea were the most commonly cited side effects of analgesics. Eighty-seven percent of patients reported concern about addiction to analgesics. Patients who believed their doctor needed to focus on curing illness rather than on controlling pain tended to comply with analgesic prescriptions (r = 0.20, p < 0.05). Patients with concerns that analgesics may cause confusion were less likely to take any type of analgesics (r = -0.16, p < 0.05). The study confirms that a patient's perceived barriers influence their decision to take analgesics, and also suggests that African American cancer patients may benefit from education that prevents misconceptions about analgesic use.

  11. Making sense of HIV testing: social representations in young Africans' HIV-related narratives from six countries.

    PubMed

    Beres, Laura K; Winskell, Kate; Neri, Elizabeth M; Mbakwem, Benjamin; Obyerodhyambo, Oby

    2013-01-01

    HIV testing and counselling are a critical intervention to support treatment access and prevent new infections. Despite high rates of infection, few young Africans know their HIV status. With the aim of informing initiatives that encourage HIV testing and access to testing benefits, this study seeks to understand how young Africans make sense of HIV testing. We conducted thematic narrative-based analysis of a stratified random sample (n = 586, ≈ 5%) from 11,354 narratives written in 2005 by males and females aged 10-24 from six sub-Saharan African countries for the 'Scenarios from Africa' scriptwriting contest which invites young people to contribute ideas for short films about HIV. The factors represented by the young authors as influencing testing behaviour and outcomes are complex and interactive, indicating that interventions that are not contextually appropriate are unlikely to affect a shift towards increased testing or improved post-testing outcomes. The narratives point to opportunities to increase HIV testing in this demographic.

  12. The Development and Evaluation of a Portion Plate for Youth: A Pilot Study

    ERIC Educational Resources Information Center

    Bohnert, Amy M.; Randall, Edin T.; Tharp, Stephanie; Germann, Julie

    2011-01-01

    Objective: To develop and evaluate a portion plate for adolescents (Nutri-plate). Methods: Sixteen African American adolescents (mean age = 12.94 years; 66% male) were randomized to participate in either plate design or nutrition education sessions. Adolescents' input was used to create the Nutri-plate, and participants' food selection and intake…

  13. Focusing of relative plate motion at a continental transform fault: Cenozoic dextral displacement >700 km on New Zealand's Alpine Fault, reversing >225 km of Late Cretaceous sinistral motion

    NASA Astrophysics Data System (ADS)

    Lamb, Simon; Mortimer, Nick; Smith, Euan; Turner, Gillian

    2016-03-01

    The widely accepted ˜450 km Cenozoic dextral strike-slip displacement on New Zealand's Alpine Fault is large for continental strike-slip faults, but it is still less than 60% of the Cenozoic relative plate motion between the Australian and Pacific plates through Zealandia, with the remaining motion assumed to be taken up by rotation and displacement on other faults in a zone up to 300 km wide. We show here that the 450 km total displacement across the Alpine Fault is an artifact of assumptions about the geometry of New Zealand's basement terranes in the Eocene, and the actual Cenozoic dextral displacement across the active trace is greater than 665 km, with more than 700 km (and <785 km since 25 Ma) occurring in a narrow zone less than 10 km wide. This way, the Alpine Fault has accommodated almost all (>94%) of the relative plate motion in the last 25 Ma at an average rate in excess of 28 mm/yr. It reverses more than 225 km (and <300 km) of sinistral shear through Zealandia in the Late Cretaceous, when Zealandia lay on the margin of Gondwana, providing a direct constraint on the kinematics of extension between East and West Antarctica at this time.

  14. Influence of relative rolling reduction and thickness layers bimetallic plate at the non-uniformity of the strain after rolling process

    NASA Astrophysics Data System (ADS)

    Rydz, D.; Stradomski, G.; Dyja, H.

    2017-02-01

    In the article were made numerical and laboratory tests of two-layers rolling process sheet composed of Al99,8 + M1E. Laboratory tests made with use of 150 mm diameter working rolls mill. To the modeling of the bimetallic plate rolling were taken the FEM Forge 2D software based on the theory of plasticity and MathCad program (in which to the rolling process modeling were used the mathematical model developed in the work [5] based on the theory of viscoelasticity). The aim of study was to determine the influence of layer thickness HT0/HM0 and relative deformation ε on the uneven distribution of steel sheet deformation after rolling process. Calculations based on the theory of viscoelasticity allowed additionally take into account the impact of the delayed effects of the variation of viscoelastic deformation of layers of the bimetallic plate rolling process.

  15. The interpretation of crustal dynamics data in terms of plate interactions and active tectonics of the Anatolian plate and surrounding regions in the Middle East

    NASA Technical Reports Server (NTRS)

    Toksoz, M. Nafi; Reilinger, Robert

    1992-01-01

    A detailed study was made of the consequences of the Arabian plate convergence against Eurasia and its effects on the tectonics of Anatolia and surrounding regions of the eastern Mediterranean. A primary source of information is time rates of change of baseline lengths and relative heights determined by repeated SLR measurements. These SLR observations are augmented by a network of GPS stations in Anatolia, Aegea, and Greece, established and twice surveyed since 1988. The existing SLR and GPS networks provide the spatial resolution necessary to reveal the details of ongoing tectonic processes in this area of continental collision. The effort has involved examining the state of stress in the lithosphere and relative plate motions as revealed by these space based geodetic measurements, seismicity, and earthquake mechanisms as well as the aseismic deformations of the plates from conventional geodetic data and geological evidence. These observations are used to constrain theoretical calculations of the relative effects of: (1) the push of the Arabian plate; (2) high topography of Eastern Anatolia; (3) the geometry and properties of African-Eurasian plate boundary; (4) subduction under the Hellenic Arc and southwestern Turkey; and (5) internal deformation and rotation of the Anatolian plate.

  16. Late Cretaceous/early Tertiary convergence between the Indian and Arabian plates recorded in ophiolites and related sediments

    NASA Astrophysics Data System (ADS)

    Gnos, E.; Immenhauser, A.; Peters, Tj.

    1997-03-01

    Remnants of ocean floor forming the Eastern Ophiolite Belt in Oman and the Western Ophiolite Belt in Pakistan have a common plate-tectonic history culminating in emplacement at the Cretaceous/Tertiary boundary. Fragments of ocean floor in these two belts have ages between 150 and 65 Ma and recorded tectonic events in the early Indian Ocean at 150 Ma, 130-120 Ma, 110-100 Ma and 70-65 Ma. New radiometric and chronostratigraphic ages and paleomagnetic and sedimentary information are used to relocate these ophiolites in the frame of the evolving Indian Ocean, which was characterised by the stepwise breakup of Gondwana at 158 Ma (East and West Gondwana), 130 Ma (Southern Atlantic, breakup of East Gondwana), 95-84 Ma (Madagascar and India/Seychelles), 65 Ma (India and Seychelles) and, finally, at 40 Ma, rifting between Africa and Arabia. The 150-Ma-old oceanic rocks of Masirah Island in Oman originally formed the extension of the basins now preserved along the eastern edge of the Afro-Arabian plate. Masirah drifted together with India-Seychelles when a new ridge formed at approximately 130 Ma separating microplates (e.g., Kabul Block) from the northern edge of Greater India. Parts of this new ocean were later emplaced to form the western ophiolite belt in Pakistan. Consumption of oceanic crust and emplacement of ophiolites during the closure of the Neotethys occurred not only north of India (± Seychelles), but also along two or three subduction zones between the Afro-Arabian plate and India/Seychelles, documented by the formation of metamorphic soles beneath ophiolites. Relics of ocean floor formed approximately 65-70 Ma ago, now form the upper units in the Western Ophiolite belt of Pakistan where they overlie an accretionary prism of pillow lavas of dominantly (Aptian-) Albian age and sedimentary rocks. The breakup of India and the Seychelles at 65 Ma was associated with the eruption of flood basalts (Deccan and Seychelles) and enhanced counter-clockwise movement of

  17. Peen plating

    NASA Technical Reports Server (NTRS)

    Babecki, A. J. (Inventor); Haehner, C. L.

    1973-01-01

    A process for metal plating which comprises spraying a mixture of metallic powder and small peening particles at high velocity against a surface is described. The velocity must be sufficient to impact and bond metallic powder onto the surface. In the case of metal surfaces, the process has as one of its advantages providing mechanical working (hardening) of the surface simultaneously with the metal plating.

  18. Correlation between plate motions and tectonic subsidence of sedimentary basins in Africa

    SciTech Connect

    Janssen, M.E. )

    1993-09-01

    From the early Mesozoic until the Holocene, the African continent was generally in a state of extension, based on plate tectonic reconstructions and sedimentary basin subsidence studies. Beginning with the breakup of Gondwana in the Permian-Triassic, this resulted in the formation of the present-day African continental margins and a series of intracontinental rift basins, located mainly on older (late Proterozoic) shear zones. Numerous wells from marginal, as well as intracontinental rift basins, have been backstripped to elucidate their Mesozoic and Tertiary tectonic histories. They show a generally consistent patterns of subsidence and uplift phases in all basins. During the evolution of these basins, the direction of African plate motion changed several times. This was related to the differential opening of the central and south Atlantic oceans, changes in spreading rates in both the Atlantic and Indian oceans, and the collision between Africa and Europe. Episodes of compressional deformation related to these plate tectonic changes are revealed in backstripped tectonic subsidence curves.

  19. Extraordinary high ductility/strength of the interface designed bulk W-ZrC alloy plate at relatively low temperature

    PubMed Central

    Xie, Z. M.; Liu, R.; Miao, S.; Yang, X. D.; Zhang, T.; Wang, X. P.; Fang, Q. F.; Liu, C. S.; Luo, G. N.; Lian, Y. Y.; Liu, X.

    2015-01-01

    The refractory tungsten alloys with high ductility/strength/plasticity are highly desirable for a wide range of critical applications. Here we report an interface design strategy that achieves 8.5 mm thick W-0.5 wt. %ZrC alloy plates with a flexural strength of 2.5 GPa and a strain of 3% at room temperature (RT) and ductile-to-brittle transition temperature of about 100 °C. The tensile strength is about 991 MPa at RT and 582 MPa at 500 °C, as well as total elongation is about 1.1% at RT and as large as 41% at 500 °C, respectively. In addition, the W-ZrC alloy plate can sustain 3.3 MJ/m2 thermal load without any cracks. This processing route offers the special coherent interfaces of grain/phase boundaries (GB/PBs) and the diminishing O impurity at GBs, which significantly strengthens GB/PBs and thereby enhances the ductility/strength/plasticity of W alloy. The design thought can be used in the future to prepare new alloys with higher ductility/strength. PMID:26531172

  20. The Relationship Between the Social Environment and Lifestyle-Related Physical Activity in a Low-Income African American Inner-City Southern Neighborhood.

    PubMed

    Andersen, Lori; Gustat, Jeanette; Becker, Adam B

    2015-10-01

    The social ecological model was used to examine individual, interpersonal, and neighborhood characteristics related to lifestyle-related physical activity (PA) in a low-income African American (AA) population in New Orleans, Louisiana. Interviewers administered surveys to randomly-sampled household participants from three low-income, AA neighborhoods in New Orleans, Louisiana. Questions included the social and physical environment, physical activity, interpersonal factors, demographics, height and weight. Logistic regression multivariable models were built predicting whether the respondent met PA guidelines, controlling for neighborhood. Females were less as likely to engage in lifestyle-related PA compared to males (OR 0.46, CI 0.30-0.70). Support specific for PA was correlated with engaging in lifestyle-related PA (OR 1.45, CI 1.14-1.83). The individual and social environment should be considered for increasing PA in AA. Interventions targeting the AA population could consider ways of enhancing social support for PA.

  1. Social Integration and Suicide-related Ideation from a Social Network Perspective: A Longitudinal Study among Inner-City African Americans

    PubMed Central

    Kuramoto, SJ; Wilcox, HC; Latkin, CA

    2013-01-01

    This study examined if social network density, as measured by the extent to which network members know each other, was associated with suicide-related ideation and plan approximately three years later. Eight hundred nineteen African Americans were interviewed at Wave 1 (1997–1999) and Wave 4 (2001–2003) of the Self-Help In Eliminating Life-Threatening Diseases (SHIELD) study, a HIV preventive intervention study in Baltimore, MD. Multinomial logistic regression models were used to compare risks of suicide-related ideation and plan at Wave 4 by Wave 1 density. Even after adjusting for baseline sociodemographic characteristics and depressive symptoms, individuals with lower level of density were three times more likely to report suicide-related ideation and plan in the past year at Wave 4. The findings reinforce the importance of social integration among inner-city African Americans from a social network perspective. Future research should examine the mechanisms associated with this relationship and other social network constructs. PMID:23530665

  2. African ethics and voluntary euthanasia.

    PubMed

    Omonzejele, P F

    2004-01-01

    This paper outlines the relationship between euthanasia and its ethical norms and practices in a part of West Africa. The various sub-types of euthanasia are described in detail, parallel with the role of African ethical theories in determining their relevance. The author discusses the implications of this approach relative to the social and economic state of African communities.

  3. An Introduction to West African Literature.

    ERIC Educational Resources Information Center

    Taiwo, Oladele

    Intended to provide help for those interested in studying West African literature, this book is divided into three parts. Part One provides background information: the various African oral traditions are discussed, related to the way of life of the people, and examined for the extent to which they form the basis of present West African literary…

  4. Sea Island Cascades: An Analysis of Principals' and Teachers' Perceptions of Factors Related to the Overrepresentation of African American Males Identified as Having an Emotional Disability

    ERIC Educational Resources Information Center

    Bryant, Jacinta Maria

    2014-01-01

    The issue of the overrepresentation of African Americans in special education is a persistent concern that has negatively impacted African American male students, their families, school districts, and the field of special education. School districts throughout the nation report a higher representation of African American males in special education…

  5. The relation of ethnic identification with cigarette smoking among US urban African American and Latino youth: a pilot study.

    PubMed

    Parker, V; Sussman, S; Crippens, D; Elder, P; Scholl, D

    1998-01-01

    Primarily African American and Latino seventh graders (N = 545) attending health and science classes at three urban Southern California junior high schools were administered a 13-item ethnic identification assessment during one class period, to investigate the relationship between ethnic identification and tobacco use. For African Americans, the perception of looking different from other ethnic groups was found to be associated with avoidance of peer tobacco use. Among Latinos, the perception of being liked by other ethnic groups, and enjoying interaction with people outside of their ethnic group, were found to be associated with negating peer influence for tobacco use. Watching television shows with main characters of same ethnic group was associated with being able to make friends without using tobacco, for both ethnic groups. For Latinos, ever trying a cigarette was associated with the perception of being liked by other ethnic groups. These results suggest there may be elements inherent in ethnic identification protective against peer influence for smoking among ethnic minority youth. Also, acculturation of Latinos to the majority population may increase their risk for experimentation with tobacco products.

  6. Experiences of racial discrimination and relation to sexual risk for HIV among a sample of urban black and African American men.

    PubMed

    Reed, E; Santana, M C; Bowleg, L; Welles, S L; Horsburgh, C R; Raj, A

    2013-04-01

    This study aimed to examine racial discrimination and relation to sexual risk for HIV among a sample of urban black and African American men. Participants of this cross-sectional study were black and African American men (N = 703) between the ages of 18 and 65 years, recruited from four urban clinical sites in the northeast. Multivariate logistic regression models were used to analyze the relation of reported racial discrimination to the following: (1) sex trade involvement, (2) recent unprotected sex, and (3) reporting a number of sex partners in the past 12 months greater than the sample average. The majority of the sample (96%) reported racial discrimination. In adjusted analyses, men reporting high levels of discrimination were significantly more likely to report recent sex trade involvement (buying and/or selling) (adjusted odds ratio (AOR) range = 1.7-2.3), having recent unprotected vaginal sex with a female partner (AOR = 1.4, 95% confidence interval (CI), 1.1-2.0), and reporting more than four sex partners in the past year (AOR = 1.4, 95% CI, 1.1-1.9). Findings highlight the link between experiences of racial discrimination and men's sexual risk for HIV.

  7. Caribbean plate interactions

    SciTech Connect

    Ball, M. )

    1993-02-01

    Vector analysis of plate motions, derived from studies of Atlantic magnetic lineations and fracture zone trends, indicates the following relative movements between the Caribbean, North American, and South American Plates. (1) During Early Jurassic to Early Cretaceous, the North American Plate moved 1900 km westward and 900 km northward relative to the South American Plate. A broad zone including the Caribbean region, i.e., the zone between the North and South America Plates, was a site of left-lateral shear and north-south extension. (2) During Early Cretaceous to Late Cretaceous, the North American Mate moved an additional 1200 km westward relative to South America across this zone. (3) During Late Cretaceous to the end of the Eocene, the North American Plate moved 200 km westward and 400 km northward relative to the South American Plate. (4) From the end of the Eocene to near the end of the Miocene, North America converged on South America some 200 km and moved 100 km eastward relative to it. Through the Mesozoic and earliest Tertiary history of the Caribbean, the region was a shear zone within which left-lateral displacement exceeded 3000 km and north-south extension exceeded 1300 km. In regard to time, 80% of the history of the Caribbean region is one of north-south extension and left-lateral shear. In terms of space, 97% of the shear is left-lateral and the ratio of divergence versus convergence is 7 to 1. Thus, characterizing the Caribbean region, and the Atlantic to its east, as a zone of north-south extension and left-lateral shear, is a fair generalization.

  8. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors.

  9. Feynman's wobbling plate

    NASA Astrophysics Data System (ADS)

    Tuleja, Slavomir; Gazovic, Boris; Tomori, Alexander; Hanc, Jozef

    2007-03-01

    In the book Surely You Are Joking, Mr. Feynman! Richard Feynman tells a story of a Cornell cafeteria plate being tossed into the air. As the plate spun, it wobbled. Feynman noticed a relation between the two motions. He solved the motion of the plate by using the Lagrangian approach. This solution didn't satisfy him. He wanted to understand the motion of the plate by analyzing the motion of its individual particles and the forces acting on them. He was successful, but he didn't tell us how he did it. We provide an elementary explanation for the two-to-one ratio of wobble to spin frequencies, based on an analysis of the motion of the particles and the forces acting on them. We also demonstrate the power of numerical simulation and computer animation to provide insight into a physical phenomenon and guidance on how to do the analysis.

  10. The pisiform growth plate is lost in humans and supports a role for Hox in growth plate formation

    PubMed Central

    Kjosness, Kelsey M; Hines, Jasmine E; Lovejoy, C Owen; Reno, Philip L

    2014-01-01

    The human pisiform is a small, nodular, although functionally significant, bone of the wrist. In most other mammals, including apes and Australopithecus afarensis, pisiforms are elongate. An underappreciated fact is that the typical mammalian pisiform forms from two ossification centers. We hypothesize that: (i) the presence of a secondary ossification center in mammalian pisiforms indicates the existence of a growth plate; and (ii) human pisiform reduction results from growth plate loss. To address these hypotheses, we surveyed African ape pisiform ossification and confirmed the presence of a late-forming secondary ossification center in chimpanzees and gorillas. Identification of the initial ossification center occurs substantially earlier in apes relative to humans, raising questions concerning the homology of the human pisiform and the two mammalian ossification centers. Second, we conducted histological and immunohistochemical analyses of pisiform ossification in mice. We confirm the presence of two ossification centers separated by organized columnar and hypertrophic chondrocyte zones. Flattened chondrocytes were highly mitotic, indicating the presence of a growth plate. Hox genes have been proposed to play a fundamental role in growth plate patterning. The existence of a pisiform growth plate presents an interesting test case for the association between Hox expression and growth plate formation, and could explain the severe effects on the pisiform observed in Hoxa11 and Hoxd11 knockout mice. Consistent with this hypothesis, we show that Hoxd11 is expressed adjacent to the pisiform in late-stage embryonic mouse limbs supporting a role for Hox genes in growth plate specification. This raises questions concerning the mechanisms regulating Hox expression in the developing carpus. PMID:25279687

  11. Genetic variation in the insulin, insulin-like growth factor, growth hormone, and leptin pathways in relation to breast cancer in African-American women: the AMBER consortium

    PubMed Central

    Ruiz-Narváez, Edward A; Lunetta, Kathryn L; Hong, Chi-Chen; Haddad, Stephen; Yao, Song; Cheng, Ting-Yuan David; Bensen, Jeannette T; Bandera, Elisa V; Haiman, Christopher A; Troester, Melissa A; Ambrosone, Christine B; Rosenberg, Lynn; Palmer, Julie R

    2016-01-01

    The insulin/insulin-like growth factor (IGF) system and related pathways such as growth hormone, and leptin signaling have a key role in cancer development. It is unclear how germline variation in these pathways affects breast cancer risk. We conducted gene-based analyses of 184 genes in the insulin/IGF, growth hormone, and leptin pathways to identify genetic variation associated with risk of breast cancer overall, and for estrogen receptor (ER) subtypes. Tag single-nucleotide polymorphisms (SNPs) for each gene were selected and genotyped on a customized Illumina SNP array. Imputation was carried out using 1000 Genomes haplotypes. The analysis included 91,627 SNPs genotyped or imputed in 3,663 breast cancer cases, (1,983 ER-positive and 1,098 ER-negative) and 4,687 controls from the African American Breast Cancer Epidemiology and Risk consortium, a collaborative project of four large studies of breast cancer in African-American women (Carolina Breast Cancer Study, Black Women's Health Study, Women's Circle of Health Study, and Multiethnic Cohort). We used a multi-locus adaptive joint test to determine the association of each gene with overall breast cancer and ER subtypes. The most significant gene associations (P ≤ 0.01) were BAIAP2 and CALM2 for overall breast cancer; BAIAP2 and CSNK2A1 for ER+ breast cancer; and BRAF, BAD, and MAPK3 for ER− breast cancer. The association of BAD with ER− breast cancer was explained by a two-SNP risk model; all other associations were best explained by one-SNP risk models. In total, six genes and seven SNPs had suggestive associations with overall breast cancer or ER subtypes in African-American women. PMID:27942580

  12. ANTERIOR CHAMBER DEPTH, LENS THICKNESS, AND RELATED MEASURES IN AFRICAN-AMERICAN FEMALES WITH LONG ANTERIOR ZONULES: A MATCHED STUDY WITH CONTROL FOR REFRACTIVE ERROR

    PubMed Central

    Roberts, Daniel K.; Teitelbaum, Bruce A.; Castells, David D.; Winters, Janis E.; Wilensky, Jacob T.

    2014-01-01

    Purpose To investigate anterior chamber depth (ACD), lens thickness (LT), vitreous body length (VBL), and axial length (AL) in African-American females with long anterior zonules (LAZ) while controlling for refractive error. Methods The eyes of 50 African-American females with LAZ were compared to 50 controls matched on age, race, sex, and refractive error. Central ACD, LT, VBL, and AL measurements were obtained in a masked fashion using a-scan ultrasonography. Results LAZ cases had a mean age ± SD (range) = 67.1 ± 7.6 years (52–85 years) and a mean refractive error = +1.85 ± 1.41D (−1.75 to +4.75D). Parameters were similar for controls. Mean ACD for cases was 2.45 ± 0.34 mm and 2.57 ± 0.38 mm for controls. Mean LT for cases was 4.94 ± 0.43 mm and 4.83 ± 0.45 mm for controls. Mean VBL for cases was 15.00 ± 0.72 mm and 15.17 ± 0.76 mm for controls. Mean AL for cases was 22.39 ± 0.82 mm and 22.57 ± 0.76 mm for controls. Using multiple logistic regression to control for any residual differences in age and refractive error, no significant differences were present between LAZ eyes and control eyes relative to the a-scan variables (P>0.1). Conclusions When refractive error was controlled for, this group of African-American females with LAZ did not exhibit clinically significant differences in ACD, LT, VBL, and AL as compared to controls. PMID:25093521

  13. Convective Removal of Continental Margin Lithosphere at the Edges of Subducting Oceanic Plates

    NASA Astrophysics Data System (ADS)

    Levander, A.; Bezada, M. J.; Palomeras, I.; Masy, J.; Humphreys, E.; Niu, F.

    2013-12-01

    Although oceanic lithosphere is continuously recycled to the deeper mantle by subduction, the rates and manner in which different types of continental lithospheric mantle are recycled is unclear. Cratonic mantle can be chemically reworked and essentially decratonized, although the frequency of decratonization is unclear. Lithospheric mantle under or adjacent to orogenic belts can be lost to the deeper mantle by convective downwellings and delamination phenomena. Here we describe how subduction related processes at the edges of oceanic plates adjacent to passive continental margins removes the mantle lithosphere from beneath the margin and from the continental interior. This appears to be a widespread means of recycling non-cratonic continental mantle. Lithospheric removal requires the edge of a subducting oceanic plate to be at a relatively high angle to an adjacent passive continental margin. From Rayleigh wave and body wave tomography, and receiver function images from the BOLIVAR and PICASSO experiments, we infer large-scale removal of continental margin lithospheric mantle from beneath 1) the northern South American plate margin due to Atlantic subduction, and 2) the Iberian and North African margins due to Alboran plate subduction. In both cases lithospheric mantle appears to have been removed several hundred kilometers inland from the subduction zones. This type of ';plate-edge' tectonics either accompanies or pre-conditions continental margins for orogenic activity by thinning and weakening the lithosphere. These processes show the importance of relatively small convective structures, i.e. small subducting plates, in formation of orogenic belts.

  14. Bibliometric Assessment of European and Sub-Saharan African Research Output on Poverty-Related and Neglected Infectious Diseases from 2003 to 2011

    PubMed Central

    Gurney, Karen A.; Mgone, Charles S.

    2015-01-01

    Background The European & Developing Countries Clinical Trials Partnership (EDCTP) is a partnership of European and sub-Saharan African countries that aims to accelerate the development of medical interventions against poverty-related diseases (PRDs). A bibliometric analysis was conducted to 1) measure research output from European and African researchers on PRDs, 2) describe collaboration patterns, and 3) assess the citation impact of clinical research funded by EDCTP. Methodology/Principal Findings Disease-specific research publications were identified in Thomson Reuters Web of Science using search terms in titles, abstracts and keywords. Publication data, including citation counts, were extracted for 2003–2011. Analyses including output, share of global papers, normalised citation impact (NCI), and geographical distribution are presented. Data are presented as five-year moving averages. European EDCTP member countries accounted for ~33% of global research output in PRDs and sub-Saharan African countries for ~10% (2007–2011). Both regions contributed more to the global research output in malaria (43.4% and 22.2%, respectively). The overall number of PRD papers from sub-Saharan Africa increased markedly (>47%) since 2003, particularly for HIV/AIDS (102%) and tuberculosis (TB) (81%), and principally involving Southern and East Africa. For 2007–2011, European and sub-Saharan African research collaboration on PRDs was highly cited compared with the world average (NCI in brackets): HIV/AIDS 1.62 (NCI: 1.16), TB 2.11 (NCI: 1.06), malaria 1.81 (NCI: 1.22), and neglected infectious diseases 1.34 (NCI: 0.97). The NCI of EDCTP-funded papers for 2003–2011 was exceptionally high for HIV/AIDS (3.24), TB (4.08) and HIV/TB co-infection (5.10) compared with global research benchmarks (1.14, 1.05 and 1.35, respectively). Conclusions The volume and citation impact of papers from sub-Saharan Africa has increased since 2003, as has collaborative research between Europe and

  15. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-04

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction.

  16. Prevalence of pain-related single nucleotide polymorphisms in patients of African origin with sickle cell disease

    PubMed Central

    Jhun, Ellie H; Yao, Yingwei; He, Ying; Kyle, Mack A; Wilkie, Diana J; Molokie, Robert E; Wang, Zaijie Jim

    2016-01-01

    Background Prospective pain genetics research is hindered by a lack of data on the prevalence of polymorphisms in pain-relevant genes for patients with sickle cell disease (SCD). For African–Americans in general, limited information is available in public databases. Methods We prioritized and examined the genotype and allele frequencies of 115 SNPs from 49 candidate pain genes in 199 adult African–Americans and pediatric patients of African origin with SCD. Analyses were performed and compared with available data from public databases. Results Genotype and allele frequencies of a number of SNPs were found to be different between our cohort and those from the databases and between adult and pediatric subjects. Conclusion As pain therapy is inadequate in a significant percentage of patients with SCD, candidate pain genetic studies may aid in designing precision pain medicine. We provide prevalence data as a reference for prospective genetic studies in this population. PMID:26555434

  17. Coccidioidomycosis in African Americans

    PubMed Central

    Ruddy, Barbara E.; Mayer, Anita P.; Ko, Marcia G.; Labonte, Helene R.; Borovansky, Jill A.; Boroff, Erika S.; Blair, Janis E.

    2011-01-01

    Coccidioidomycosis is caused by Coccidioides species, a fungus endemic to the desert regions of the southwestern United States, and is of particular concern for African Americans. We performed a PubMed search of the English-language medical literature on coccidioidomycosis in African Americans and summarized the pertinent literature. Search terms were coccidioidomycosis, Coccidioides, race, ethnicity, African, black, and Negro. The proceedings of the national and international coccidioidomycosis symposia were searched. All relevant articles and their cited references were reviewed; those with epidemiological, immunologic, clinical, and therapeutic data pertaining to coccidioidomycosis in African Americans were included in the review. Numerous studies documented an increased predilection for severe coccidioidal infections, coccidioidomycosis-related hospitalizations, and extrapulmonary dissemination in persons of African descent; however, most of the published studies are variably problematic. The immunologic mechanism for this predilection is unclear. The clinical features and treatment recommendations are summarized. Medical practitioners need to be alert to the possibility of coccidioidomycosis in persons with recent travel to or residence in an area where the disease is endemic. PMID:21193657

  18. Making sense of condoms: social representations in young people's HIV-related narratives from six African countries.

    PubMed

    Winskell, Kate; Obyerodhyambo, Oby; Stephenson, Rob

    2011-03-01

    Condoms are an essential component of comprehensive efforts to control the HIV epidemic, both for those who know their status and for those who do not. Although young people account for almost half of all new HIV infections, reported condom use among them remains low in many sub-Saharan African countries. In order to inform education and communication efforts to increase condom use, we examined social representations of condoms among young people aged 10-24 in six African countries/regions with diverse HIV prevalence rates: Swaziland, Namibia, Kenya, South-East Nigeria, Burkina Faso, and Senegal. We used a unique data source, namely 11,354 creative ideas contributed from these countries to a continent-wide scriptwriting contest, held from 1(st) February to 15(th) April 2005, on the theme of HIV/AIDS. We stratified each country sample by the sex, age (10-14, 15-19, 20-24), and urban/rural location of the author and randomly selected up to 10 narratives for each of the 12 resulting strata, netting a total sample of 586 texts for the six countries. We analyzed the narratives qualitatively using thematic data analysis and narrative-based methodologies. Differences were observed across settings in the prominence accorded to condoms, the assessment of their effectiveness, and certain barriers to and facilitators of their use. Moralization emerged as a key impediment to positive representations of condoms, while humour was an appealing means to normalize them. The social representations in the narratives identify communication needs in and across settings and provide youth-focused ideas and perspectives to inform future intervention efforts.

  19. Making sense of condoms: social representations in young people’s HIV-related narratives from six African countries

    PubMed Central

    Winskell, Kate; Obyerodhyambo, Oby; Stephenson, Rob

    2011-01-01

    Condoms are an essential component of comprehensive efforts to control the HIV epidemic, both for those who know their status and for those who do not. Although young people account for almost half of all new HIV infections, reported condom use among them remains low in many sub-Saharan African countries. In order to inform education and communication efforts to increase condom use, we examined social representations of condoms among young people aged 10–24 in six African countries/regions with diverse HIV prevalence rates: Swaziland, Namibia, Kenya, South-East Nigeria, Burkina Faso, and Senegal. We used a unique data source, namely 11,354 creative ideas contributed from these countries to a continent-wide scriptwriting contest, held from 1st February to 15th April 2005, on the theme of HIV/AIDS. We stratified each country sample by the sex, age (10–14, 15–19, 20–24), and urban/rural location of the author and randomly selected up to 10 narratives for each of the 12 resulting strata, netting a total sample of 586 texts for the six countries. We analyzed the narratives qualitatively using thematic data analysis and narrative-based methodologies. Differences were observed across settings in the prominence accorded to condoms, the assessment of their effectiveness, and certain barriers to and facilitators of their use. Moralization emerged as a key impediment to positive representations of condoms, while humour was an appealing means to normalize them. The social representations in the narratives identify communication needs in and across settings and provide youth-focused ideas and perspectives to inform future intervention efforts. PMID:21388731

  20. Towards an Africological Pedagogical Approach to African Civilization.

    ERIC Educational Resources Information Center

    Okafor, Victor Oguejiofor

    1996-01-01

    Presents a case study of controversies related to African studies and makes the case for an Africological pedagogical approach to African Civilization. The title "African Civilization" reflects the African place in the whole of world civilization even though that place is itself a multiple entity. (SLD)

  1. Evolutionary plasticity in coccidia - striking morphological similarity of unrelated coccidia (apicomplexa) from related hosts: Eimeria spp. from African and Asian Pangolins (Mammalia: Pholidota).

    PubMed

    Jirků, Miloslav; Kvičerová, Jana; Modrý, David; Hypša, Václav

    2013-07-01

    Two morphologically similar, but phylogenetically unrelated Eimeria species from ancient mammals, African Tree Pangolin Phataginus tricuspis and Sunda Pangolin Manis javanica (Pholidota: Manidae), from two distant biogeographic realms (Afrotropical and Oriental), are characterized and compared morphologically and molecularly. Phylogenetic analyses produced an unstable topology. However, while precise position of the two Eimeria species from pangolins could not be firmly established due to the lack of related taxa, it is evident that they are not closely related and do not fall into any of the so far recognized eimerian lineages. Moreover, an eimerian found in P. tricuspis is described as a new species Eimeria nkaka n. sp., based on morphology of oocysts, endogenous developmental stages and sequence data.

  2. Familial clustering of risk factors for cardiovascular disease among first-degree relatives of patients with chronic kidney disease in a sub-Saharan African population

    PubMed Central

    Raji, Yemi; Mabayoje, Omolara; Bello, Taslim

    2015-01-01

    Summary Objective To determine the prevalence of risk factors for cardiovascular disease (CVD) in first-degree relatives (FDRs) of patients with chronic kidney disease (CKD) in a sub-Saharan African population. Methods This was a cross-sectional survey of 460 subjects (230 FDRs of patients with CKD and 230 healthy controls). Anthropometrics and blood pressures were measured. Spot urine and fasting venous blood samples were obtained for biochemical analysis. Results The prevalence of hypertension, diabetes mellitus, obesity and dyslipidaemia were significantly higher in FDRs of patients with CKD compared with the controls: 56 (24.3%) vs 29 (12.6%), p = 0.01; 20 (8.7%) vs 6 (2.6%), p = 0.01; 40 (17.4%) vs 24 (10.4%), p = 0.03 and 171 (74.3%) vs 138 (60.0%), p = 0.01, respectively. Hypertension (OR, 1.65), dyslipidaemia (OR, 1.72) and albuminuria (OR, 1.61) were independently associated with being a FDR of patients with CKD. Conclusion In this sub-Saharan African population, risk factors for CVD were more prevalent in the FDRs of patients with CKD than in healthy controls. PMID:25962941

  3. Oncology pharmacy units: a safety policy for handling hazardous drugs and related waste in low- and middle-income African countries—Angolan experience

    PubMed Central

    da Conceição, Ana Vaz; Bernardo, Dora; Lopes, Lygia Vieira; Miguel, Fernando; Bessa, Fernanda; Monteiro, Fernando; Santos, Cristina; Oliveira, Blasques; Santos, Lúcio Lara

    2015-01-01

    In African countries, higher rates of late-stage cancers at the time of first diagnosis are a reality. In this context, hazardous drugs (HDs), such as chemotherapy, play an important role and have immense benefits for patients’ treatment. HDs should be handled under specific conditions. At least a class 5 environment primary engineering control (PEC), physically located in an appropriate buffer area, is mandatory for sterile HDs compounding, as well as administrative control, personal protective equipment, work practices and other engineering and environmental controls, in order to protect the environment, patient, and worker. The aim of this study is to describe the Angolan experience regarding the development of oncology pharmacy units and discuss international evidence-based guidelines on handling HDs and related waste. Measures to incorporate modern and economical solutions to upgrade or build adequate and safe facilities and staff training, in order to comply with international guidelines in this area, are crucial tasks for African countries of low and middle income. PMID:26557873

  4. The relative role of ocean-atmosphere interaction and African easterly waves in the generation and development of Tropical cyclones in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Cabos, William; Sein, Dmitry; Hodges, Kevin; Jacob, Daniela

    2016-04-01

    We use the regionally coupled ocean - atmosphere model ROM and its atmospheric component REMO in standalone configuration in order to assess the relative role of ocean feedbacks and the African easterly waves in the simulation of tropical cyclonic activity in the Atlantic ocean. To this end, a number of coupled and uncoupled simulations forced by ERA-Interim boundary conditions have been carried out. In one set of simulations, the atmospheric domain includes the Northern Africa land masses, where the easterly waves are formed. In a second set of simulations, the easterly waves are taken from the ERA Interim reanalysis, as atmospheric domain excludes explicitly the African land masses. We study the statistics of modeled tracks of the tropical cyclones in the simulations. We found that the coupling has a strong impact on the number of tropical cyclones generated in the Northern Tropical Atlantic. In the coupled run it was close to the observations, while in the uncoupled runs the number of tropical cyclones was strongly overestimated. The coupling also influences the simulated position of the ITCZ.

  5. Molecular Variation of Adh and P6 Genes in an African Population of Drosophila Melanogaster and Its Relation to Chromosomal Inversions

    PubMed Central

    Benassi, V.; Aulard, S.; Mazeau, S.; Veuille, M.

    1993-01-01

    Four-cutter molecular polymorphism of Adh and P6, and chromosome inversion polymorphism of chromosome II were investigated in 95 isogenic lines of an Ivory Coast population of Drosophila melanogaster, a species assumed to have recently spread throughout the world from a West African origin. The P6 gene showed little linkage disequilibrium with the In(2L)t inversion, although it is located within this inversion. This suggests that the inversion and the P6 locus have extensively exchanged genetic information through either double crossover or gene conversion. Allozymic variation in ADH was in linkage disequilibrium with In(2L)t and In(2R)NS inversions. Evidence suggests either that inversion linkage with the Fast allele is selectively maintained, or that this allele only recently appeared. Molecular polymorphism at the Adh locus in the Ivory Coast is not higher than in North American populations. New haplotypes specific to the African population were found, some of them connect the ``Wa(s)-like'' haplotypes found at high frequencies in the United States to the other slow haplotypes. Their relation with In(2L)t supports the hypothesis that Wa(s) recently recombined away from an In(2L)t chromosome which may be the cause of its divergence from the other haplotypes. PMID:8349110

  6. Preventing HIV among Latino and African American Gay and Bisexual Men in a Context of HIV-Related Stigma, Discrimination, and Homophobia: Perspectives of Providers

    PubMed Central

    Brooks, Ronald A.; Etzel, Mark A.; Hinojos, Ernesto; Henry, Charles L.; Perez, Mario

    2005-01-01

    HIV-related stigma, discrimination, and homophobia impede community based efforts to combat HIV disease among Latino and African American gay and bisexual men. This commentary highlights ways to address these social biases in communities of color in Los Angeles from the perspectives of staff from HIV prevention programs. Information was collected from HIV prevention program staff participating in a two-day symposium. The outcomes from the symposium offer strategies for developing and implementing HIV prevention services for Latino and African American gay and bisexual men, which include: 1) addressing social biases present in a community that can hinder, and even prohibit, utilization of effective HIV prevention programs; 2) recasting HIV prevention messages in a broader social or health context; 3) developing culturally appropriate HIV prevention messages; 4) exploring new modalities and venues for delivering HIV prevention messages that are appropriate for gay and bisexual men of color and the communities in which they live; and 5) broadening the target of HIV prevention services to include service providers, local institutions and agencies, and the community at-large. These strategies underscore the need to consider the social and contextual factors of a community when designing and implementing HIV prevention programs. PMID:16283834

  7. The Effects of a Mass Media HIV-Risk Reduction Strategy on HIV-Related Stigma and Knowledge Among African American Adolescents

    PubMed Central

    Valois, Robert F.; DiClemente, Ralph J.; Carey, Michael P.; Stanton, Bonita; Romer, Daniel; Fletcher, Faith; Farber, Naomi; Brown, Larry K.; Vanable, Peter A.; Salazar, Laura F.; Juzang, Ivan; Fortune, Thierry

    2015-01-01

    Abstract HIV-related stigma undermines HIV prevention, testing, and treatment. Multipronged risk-reduction strategies may reduce stigma among African American adolescents. To test the effectiveness of a risk-reduction strategy in addressing stigma, 1613 African American adolescents from four mid-sized cities participated in a randomized control trial. Participants received a sexual-risk reduction [Focus on Youth (FOY)] or general health curriculum [Promoting Health Among Teens (PHAT)]. Two cities received a culturally-tailored media intervention. Participants completed baseline, 3-, 6-, and 12-month surveys to measure HIV-related stigma and knowledge. Analysis of covariance tested for stigma and knowledge differences by media city status and curriculum/media city status (PHAT media vs. PHAT non-media, FOY media vs. FOY non-media; FOY media vs. PHAT media; FOY non-media vs. PHAT non-media) at each measurement. Hierarchical linear modeling (HLM) determined stigma and knowledge differences over time. Media participants demonstrated greater HIV-related knowledge (p<0.10) at 6 months and lower stigma at 3 months (p<0.10). FOY media participants had lower 3-month (p<0.05) and 12-month (p<0.10) stigma scores than non-media FOY participants. FOY media and non-media participants had greater knowledge than PHAT for all intervals after baseline. FOY media had lower stigma than PHAT media after baseline for all intervals after baseline. HLM indicated greater knowledge slopes for the media group (p<0.05). FOY media participants had greater knowledge slopes (p<0.05) relative to non-media FOY participants and media PHAT participants (p<0.01). A combination of a HIV risk-reduction curriculum and culturally-tailored media demonstrated some effectiveness in reducing stigma. Future use of media in HIV-prevention should include and evaluate effects on stigma. PMID:25738952

  8. Social support buffering of the relation between low income and elevated blood pressure in at-risk African-American adults.

    PubMed

    Coulon, S M; Wilson, D K

    2015-10-01

    Socioeconomic disadvantage has been linked to elevated blood pressure (BP), and the purpose of this study was to assess whether interpersonal social supports buffer these adverse relations in African-American adults. In three communities matched demographically, a subsample of participants (N = 204) of the Positive Action for Today's Health trial provided measures of perceived social support, annual household income, and BP. Multiple regression analyses with cross-product interactions were conducted using follow-up data. The sample had a mean age of 52.8 years (SD = 15.1), and was predominantly female (66 %) with a high body mass index (M = 33.5, SD = 14.7). Results indicated an inverse relation between social support and diastolic BP (B = -.178, p = .005), and also an interaction with income (p = .046), such that higher social support related to lower diastolic BP in the lowest-income individuals (B = -1.05). The same direct (B = -.141, p = .025) and interacting (B = -1.42, p = .040) social support effects were present for systolic BP, however the omnibus model for systolic BP was not significant, F(6, 196) = 1.80, p = .09. The hypothesized buffering effect of social support on the adverse relation of income to BP was partially supported in at-risk African-American adults. Future prevention efforts for reducing the impact of socioeconomic stress on BP may aim to increase perceptions of social support.

  9. Multiple-Dynode-Layer Microchannel Plate

    NASA Technical Reports Server (NTRS)

    Woodgate, Bruce E.

    1990-01-01

    Improved microchannel-plate electron image amplifier made of stack of discrete microchannel-plate layers. New plates easier to manufacture because no need to etch long, narrow holes, to draw and bundle thin glass tubes, or to shear plates to give microchannels curvatures necessary for reduction of undesired emission of ions. Discrete dynode layers stacked with slight offset from layer to layer to form microchannel plate with curved channels. Provides for relatively fast recharging of microchannel dynodes, with consequent enhancement of performance.

  10. Ion plating for the future

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    The ion plating techniques are classified relative to the instrumental set up, evaporation media, and mode of transport. A distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. And on the industrial level, the performance and potential uses of ion plated films are discussed.

  11. African-American spirituality: a concept analysis.

    PubMed

    Newlin, Kelley; Knafl, Kathleen; Melkus, Gail D'Eramo

    2002-12-01

    Culturally competent care for African Americans requires sensitivity to spirituality as a component of the cultural context. To foster understanding, measurement, and delivery of the spiritual component of culturally competent care, this article presents an evolutionary concept analysis of African-American spirituality. The analysis is based on a sample of multidisciplinary research studies reflecting spirituality of African Americans. Findings indicate that African-American spirituality involves quintessential, internal, external, consoling, and transformative attributive dimensions. Findings are considered in relation to previous conceptual analyses of spirituality and suggest that defining attributes of African-American spirituality are both global and culturally prominent. Implications for practice and research are discussed.

  12. Role of Pan-African Structures in Intraplate Seismicity in Ghana

    NASA Astrophysics Data System (ADS)

    Attoh, K.

    2004-05-01

    The setting for intraplate seismicity in southeastern Ghana has been cited as an analog to the even more destructive earthquakes in eastern North America such as at Charleston 1886 (Sykes 1978). Although located far away from any plate boundary, major earthquakes have occurred near Accra, the capital of Ghana in 1939 (M6.4), 1964, 1969, and most recently in 1997 (M4.8) and 2003 (M3.8). The setting for this seismic activity, near the eastern termination of the Romanche Fracture Zone (RFZ), presents the opportunity to investigate the relationship among Pan-African (Neoproterozoic) orogenic structures, transform tectonics, and neotectonic activity. Across the Ghana seismic zone prominent structures of the Pan-African orogen include: i) the Pan-African front (PF) representing the western limit of deformation, ii) the Pan-African suture zone (PS) represented by a ductile shear zone at the base of mafic granulites which comprise the suture zone nappes, and iii) a dexteral shear zone that projects into the RFZ represented by a prominent submarine canyon. Epicentral data compiled from local and teleseismic networks reveal clusters along the PF, a remarkable alignment of epicenters along the PS, and events along the coastline parallel Accra fault. Seismic reflection data offshore Ghana confirm active displacement along the Accra fault and, for the first time, provide direct evidence for neotectonic activity along the Pan-African front. The normal sense of displacement along the PF, inferred from the seismic sections, suggests that reactivation of the Pan-African structures involved inversion. The available data provide no support for active tectonics associated with the termination of the RFZ. However, reported seismic activity along the conjugate margin in northeastern Brazil suggests that far-field stresses related to active plate displacements in the Atlantic may contribute to the intraplate seismicity on these nominally passive paleo-transform margins.

  13. Ultra high-performance liquid chromatography with high-resolution mass spectrometry analysis of African mango (Irvingia gabonensis) seeds, extract, and related dietary supplements.

    PubMed

    Sun, Jianghao; Chen, Pei

    2012-09-05

    Dietary supplements based on an extract from Irvingia gabonensis (African mango, AM) seeds are one of the popular herbal weight loss dietary supplements in the U.S. market. The extract is believed to be a natural and healthy way to lose weight and improve overall health. However, the chemical composition of AM-based dietary supplements (AMDSs) has never been reported. In this study, the chemical constituents of AM seeds, AM seeds extract (AMSE), and different kinds of commercially available AMDSs have been investigated using an ultra high-performance liquid chromatography with high resolution mass spectrometry method. Ellagic acid, mono-, di-, and tri-O-methyl-ellagic acids, and their glycosides were found as major components in AM seeds. These compounds may be used for quality control of AM extract and related dietary supplements.

  14. Generating Conflict for Greater Good: Utilizing Contingency Theory to Assess Black and Mainstream Newspapers as Public Relations Vehicles to Promote Better Health among African Americans

    PubMed Central

    Lumpkins, Crystal Y.; Bae, Jiyang; Cameron, Glen T.

    2010-01-01

    The potential use of strategic conflict management ( Wilcox and Cameron, 2006; Cameron, Wilcox, Reber and Shin ( in press) as a health advocacy tool in US African-American and mainstream newspapers, arguing that escalation of conflict can increase effectiveness of health-related news releases. For health communicators focusing on at-risk populations with poor health outcomes, such goals would include increased awareness of health problems and solutions, along with increased motivation arising from indignation over health disparities. Content analysis of 1,197 stories in 24 Black and 12 mainstream newspapers showed that more conflict factors were present in Black vs. mainstream newspapers, suggesting a way to strategically place health messages in news releases disseminated to newspapers that motivate at-risk publics to better health. The findings suggest that conflict factors such as racial disparity data regarding health issues may enhance media advocacy. PMID:22822291

  15. Generating Conflict for Greater Good: Utilizing Contingency Theory to Assess Black and Mainstream Newspapers as Public Relations Vehicles to Promote Better Health among African Americans.

    PubMed

    Lumpkins, Crystal Y; Bae, Jiyang; Cameron, Glen T

    2010-03-01

    The potential use of strategic conflict management ( Wilcox and Cameron, 2006; Cameron, Wilcox, Reber and Shin ( in press) as a health advocacy tool in US African-American and mainstream newspapers, arguing that escalation of conflict can increase effectiveness of health-related news releases. For health communicators focusing on at-risk populations with poor health outcomes, such goals would include increased awareness of health problems and solutions, along with increased motivation arising from indignation over health disparities. Content analysis of 1,197 stories in 24 Black and 12 mainstream newspapers showed that more conflict factors were present in Black vs. mainstream newspapers, suggesting a way to strategically place health messages in news releases disseminated to newspapers that motivate at-risk publics to better health. The findings suggest that conflict factors such as racial disparity data regarding health issues may enhance media advocacy.

  16. African Aesthetics

    ERIC Educational Resources Information Center

    Abiodun, Rowland

    2001-01-01

    No single traditional discipline can adequately supply answers to the many unresolved questions in African art history. Because of the aesthetic, cultural, historical, and, not infrequently, political biases, already built into the conception and development of Western art history, the discipline of art history as defined and practiced in the West…

  17. African Pentecostalism

    ERIC Educational Resources Information Center

    Garrard, David J.

    2009-01-01

    The diversity of African Pentecostalism, its early colonial and missionary history and its current characteristics are described and analysed. Reference is made to methods of training and forms of leadership, and suggestions are made about the reasons for its growth and persistence. (Contains 19 notes.)

  18. Plate electronics

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    Using a Cray T3D supercomputer and a simple assumption about the physical character of Earth's mantle, a pair of researchers from the University of California at Berkeley have built a computer model that may help explain why the planet's tectonic plates look the way they do.In creating a three-dimensional numerical simulation of convection in the Earth's interior, UC researchers Hans-Peter Bunge and Mark Richards simplified their model to account for just one major physical effect: that the viscosity of the mantle increases with depth. Reviewing some recent—but not yet widely accepted—seismic data, Bunge and Richards assumed for the sake of the model that the viscosity of the mantle increases by a factor of 30 from the lithosphere to the core-mantle boundary. Relying on that assumption, the pair ran the model for nearly three weeks on a supercomputer at Los Alamos National Laboratory and found that the simulation produced an effect similar to what we see on the surface of Earth. The model produced a surface paralleling the actual width of plates and the geometry of the plate boundaries.

  19. Earth's Decelerating Tectonic Plates (Invited)

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Moucha, R.; Rowley, D. B.; Quere, S.; Mitrovica, J. X.; Simmons, N. A.; Grand, S. P.

    2009-12-01

    We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data (Simmons et al., GJI 2009) to explore the impact of time-dependent changes in mantle buoyancy forces on tectonic plate accelerations. This plate-coupled mantle convection model incorporates a viscosity structure that reconciles both glacial isostatic adjustment and global convection-related data sets (Mitrovica & Forte, EPSL 2004) and it successfully reproduces present-day plate velocities, global surface gravity and topography data. This convection model predicts the recent deceleration of several major plates in the Pacific and Indo-Atlantic hemispheres. Independent verification of these predictions is a fundamental test of the plausibility of the buoyancy forces and rheological structure in the convection model. To this end, we consider marine magnetic anomaly and space geodetic constraints on tectonic plate motions to determine a new global map of present-day rates of change of plate velocities. This map shows that several major plates, such as the Pacific, Africa and Nazca plates are presently decelerating and that they contribute to a globally-averaged slowdown in tectonic plate speeds. These joint geologic-geodetic inferences of plate decelerations are consistent with those predicted by our tomography-based convection model.

  20. Host acceptance, suitability, and effects of host deprivation on the West African egg parasitoid Telenomus isis (Hymenoptera: Scelionidae) reared on East African stemborers under varying temperature and relative humidity regimens.

    PubMed

    Bruce, Anani Yaovi; Schulthess, Fritz; Mueke, Jones

    2009-06-01

    Scelionid egg parasitoids of Telenomus spp. have been shown to significantly affect noctuid stemborer populations and yields of maize in western Africa. One of them, T. isis, has never been reported from eastern Africa and was introduced into the laboratories of the International Centre of Insect Physiology and Ecology, Kenya. This study evaluates the biotic potential of T. isis using East African stemborers as hosts. Host acceptance was tested using 15 lepidopteran borer species. Only noctuid stemborers were accepted for oviposition by T. isis. Sesamia calamistis Hampson, Sesamia nonagrioides (Lefebvre), and Busseola fusca (Fuller) were further used to study the effect of host species, host age, duration of host deprivation, temperature, and humidity on the performance of the parasitoid. In contrast to sex ratio, developmental time, parasitism, and parasitoid emergence varied significantly with host species, and the former two decreased with the age of host eggs. Female longevity increased with duration of host deprivation, whereas average lifetime fecundity decreased, probably because of oocyte resorption. T. isis successfully developed between 18 and 32 degrees C at both low (40-50%) and high (70-80%) relative humidity regimens, but temperature played a more critical role. Using the modified Logan model, the lower and upper temperature thresholds for development were estimated at 11.5 and 37.5 degrees C, respectively, with an optimum at 30.5 degrees C for both humidity regimens. Depending on temperature and relative humidity regimen, the intrinsic rate of increase (r(m)) varied from 0.077 to 0.300, net reproductive rate (R(o)) from 7.70 to 83.96, and generation time (G) from 11 to 38 d. The results of this study indicate that T. isis is likely to establish in eastern Africa.

  1. "My hair or my health:" Overcoming barriers to physical activity in African American women with a focus on hairstyle-related factors.

    PubMed

    Huebschmann, Amy G; Campbell, Lucille Johnson; Brown, Candace S; Dunn, Andrea L

    2016-01-01

    Physical activity disparities among African American (AA) women may be related to sociocultural barriers, including difficulties with restyling hair after exercise. We sought to identify physical activity barriers and facilitators in AA women with a focus on sociocultural factors related to hairstyle maintenance. Participants (n = 51) were AA women aged 19-73 years who completed valid surveys and participated in structured focus groups, stratified by age and physical activity levels, from November 2012 to February 2013. The Constant Comparison method was used to develop qualitative themes for barriers and facilitators. The most frequently reported general physical activity barrier among exercisers was "lack of money" (27%) and among non-exercisers was "lack of self-discipline" (57%). A hairstyle-related barrier of "sweating out my hairstyle" was reported by 7% of exercisers and 29% of non-exercisers. This hairstyle-related barrier included the need for extra time and money to restyle hair due to perspiration. Hairstyle-related facilitators included: prioritizing health over hairstyle and high self-efficacy to restyle hair after perspiration. Participants were interested in resources to simplify hairstyle maintenance. AA women whose hairstyle is affected by perspiration may avoid physical activity due to time and financial burdens. Increasing self-efficacy to restyle hair after perspiration may help to overcome this barrier.

  2. Localised Plate Motion on Venus

    NASA Astrophysics Data System (ADS)

    Ghail, R. C.

    1996-03-01

    The volcanic and tectonic features observed in Dali Vinculum, Parga Vinculum and Imdr Regio are concentrated at long, narrow, curvilinear zones, with relatively minor volcanism and tectonism between these zones. These zones, whilst more diffuse than terrestrial plate boundaries, nevertheless define the margins of tectonic plates. In contrast to Earth, however, it appears that venusian plates are neither created nor destroyed by lateral motion. Rather, plates are thinned and intruded at vincula plate boundaries, vertically accreted by small-scale intra-plate (planitia) volcanism and perhaps destroyed by delamination of thickened crust in tesserae and montane regions such as Thetis Regio and Ishtar Terra. The diversity in age both between and within these three areas together with the evidence for infrequent, small scale resurfacing in the planitiae are difficult to reconcile with a non-uniformitarian geological process.

  3. Dynamics and stress field of the Eurasian plate

    NASA Astrophysics Data System (ADS)

    Warners-Ruckstuhl, Karin; Govers, Rob; Wortel, Rinus

    2013-04-01

    extent, to lithospheric density structure and normal pressure from mantle flow. Stress observations require collision forces on the India-Eurasia boundary of 7.2 - 10.5 T N/m and on the Arabia-Eurasia boundary of 1.3 - 2.3 T N/m. Implication of mechanical equilibrium of the plate is that forces on the contacts with the African and Australian plates amount to 1.0 - 2.1 and 0 - 0.8 T N/m, respectively. The inferred collision forces are part of the best-fitting overall set of forces acting on the Eurasian plate, satisfying constraints from basic mechanics, absolute plate motion and stress field. We use our results to assess the validity of the classical view that the mean elevation of an orogenic plateau can be taken as a measure of the magnitude of the compressive (in this case: collision-related) forces involved. We find that for both the Tibetan and the Iranian plateau, two plateaus with significantly different average elevations, the horizontal force derived from the excess gravitational potential energy (collapse force) is in balance with the collision force, thus confirming the hypothesis of balanced topography.

  4. The central west Saharan dust hot spot and its relation to African easterly waves and extratropical disturbances

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Todd, Martin C.

    2010-06-01

    A vast, arid, and virtually uninhabited region covering eastern Mauritania and northern Mali appears in satellite estimates of dust loading as the global maximum during boreal summer. Here the complex meteorological conditions that create this central western Sahara (CWS) dust hot spot are investigated on the basis of regression analyses and case study examples using a wide range of satellite analysis products. The results confirm the importance of African easterly waves (AEWs), previously hypothesized on the basis of case studies. The main ingredients to create this connection are as follows. (1) Strengthened southerlies to the east of an AEW trough advect moist air into the southern Sahara. Daytime heating and orography trigger moist convection in this air mass. Strong evaporation in dry midlevel air generates extended cold pools and haboob dust storms. (2) Vertical mixing brings dust into the upper parts of the deep Saharan boundary layer, from where it can be advected back into the CWS region with the northerlies ahead of the next AEW trough. (3) If the associated surface vortex is strong enough, more dust emission occurs within or just upstream of the CWS. (4) High-amplitude waves in the subtropics enhance the meridional flow associated with the AEW. Although there is a considerable case-to-case variability, it can be concluded that AEWs in concert with extratropical disturbances substantially contribute to the hot spot creation both through emission and the organization of transport. Disagreement between different satellite products and the presence of clouds complicate the analysis and underline the necessity for new observations.

  5. Studies on Zinc and Copper Ion in Relation to Wound Healing in Male and Female West African Dwarf Goats.

    PubMed

    Olaifa, A K; Fadason, S T

    2017-03-06

    Wound healing remains a challenging clinical problem for which precise and efficient management is essential in order to curtail morbidity and mortality. Wound healing has been shown to depend upon the availability of appropriate trace elements like copper and zinc which serve as enzyme cofactors and structural components in tissue repair. This study aims at evaluating the distribution of zinc and copper found in the hair as well as skin during epidermal wound healing. Adult and healthy West African dwarf (WAD) goats of both sexes fed with concentrate, grass, cassava peel and water ad libitum were used. The animals were housed for three weeks before commencement of the experiments. Epidermal wounds were created on the trunks of all the goats using cardboard template of 1cm². Progressive changes in wound contraction were monitored grossly by placing clean and sterile venier calliper on the wound margin. Hair and skin elemental (copper and zinc) analyses were done using atomic absorption spectroscopy (AAS). Significant increases in Cu level were observed in the female hair compared with that of males. There were significant increases in the Zn levels of the females' hair compared with the males. The wound healed faster in female goat compared with the males. The ratio of copper to zinc is clinically more important than the concentration of either of these trace metals. The pattern of distribution between zinc and copper concentration in the skin and hair of the male and female goats observed in this study could be added factor responsible for early wound healing in female. Therefore, our findings suggest that the distribution in the Cu and Zinc level in skin and hair of both male and female goats could also be a factor for wound healing in the animals.

  6. Association of Lipopolysaccharide-Binding Protein With Aging-Related Adiposity Change and Prediabetes Among African Ancestry Men

    PubMed Central

    Zmuda, Joseph M.; Kuipers, Allison L.; Nestlerode, Cara S.; Evans, Rhobert W.; Bunker, Clareann H.; Patrick, Alan L.

    2016-01-01

    OBJECTIVE Cross-sectional studies suggest that lipopolysaccharide-binding protein (LBP) may be associated with obesity and metabolic disorders. However, prospective studies examining LBP are lacking. This prospective study investigated the association between LBP and metabolic abnormalities in 580 African ancestry men (mean age, 59.1 ± 10.5 years). RESEARCH DESIGN AND METHODS We measured fasting serum LBP at baseline. Changes in adiposity and glucose homeostasis as well as case subjects with new type 2 diabetes and impaired fasting glucose (IFG) were assessed at a follow-up visit ˜6 years later. Baseline LBP values were tested across quartiles for linear trend with metabolic measures. Multivariable logistic regression was used to determine the odds of new cases of IFG or diabetes per 1-SD greater baseline LBP. RESULTS LBP was significantly associated with baseline BMI, waist circumference, whole-body and trunk fat, skeletal muscle density, fasting serum insulin, and HOMA-insulin resistance (IR) (all P < 0.01). Greater baseline LBP was significantly associated with longitudinal increases in the percentage of trunk fat (P = 0.025) and HOMA-IR (P = 0.034), but only borderline so with a decrease in skeletal muscle density (P = 0.057). In men with normal glucose, baseline LBP was associated with increased odds of having IFG at follow-up after adjustment for age, baseline trunk fat, and lifestyle factors (odds ratio per 1-SD LBP: 1.51; 95% CI 1.02–2.21). This association was attenuated after additional adjustment for change in trunk fat (P = 0.067). CONCLUSIONS LBP may be a marker of prediabetes. Some of this association appears to be mediated through increased central and ectopic skeletal muscle adiposity. PMID:26721818

  7. Far field effects of Alpine plate tectonism in the Iberian microplate recorded by fault-related denudation in the Spanish Central System

    NASA Astrophysics Data System (ADS)

    de Bruijne, C. H.; Andriessen, P. A. M.

    2002-05-01

    Apatite fission track analysis was performed on 56 samples from central Spain to unravel the far field effects of the Alpine plate tectonic history of Iberia. The modelled thermal histories reveal complex cooling in the Cenozoic, indicative of intermittent denudation. Accelerated cooling events occurred across the Spanish Central System (SCS) from the Middle Eocene to Recent. These accelerated cooling events resulted in up to 2.8±0.9 km of denudation in the western Sierra de Gredos and 3.6±1.0 km in the central and eastern Gredos (assuming a paleogeothermal gradient of 28±5 °C and a surface temperature of 10 °C). The greatest amount of denudation (5.0±1.6 km) occurred in the Sierra de Guadarrama. Accompanying rock uplift was 4.7±1.0 and 5.9±1.6 km in the eastern Gredos and Guadarrama, respectively. Most denudation in the Gredos occurred from the Middle Eocene to the Early Miocene and can be related to the N-S stress field, induced by the Pyrenean compression. In the Guadarrama, the greatest denudation was Pliocene to Recent of age and seems related to the ongoing NW-SE Betic compression. The fact that the formation of the E-W trending Gredos coincides with the N-S Pyrenean compression and the creation of the present day morphology of the NE-SW trending Guadarrama with the younger NW-SE Betic compression, indicates that they record the far field effects of Alpine plate tectonics on Iberia. The trend of pre-existing lineaments was of major importance in influencing the style and magnitude of these of far field effects.

  8. Social networks and social support among ball-attending African American men who have sex with men and transgender women are associated with HIV-related outcomes.

    PubMed

    Arnold, Emily A; Sterrett-Hong, Emma; Jonas, Adam; Pollack, Lance M

    2016-05-11

    The House Ball Community (HBC) is an understudied network of African American men who have sex with men and transgender women, who join family-like houses that compete in elaborate balls in cities across the United States. From 2011 to 2012, we surveyed 274 recent attendees of balls in the San Francisco Bay Area, focusing on social networks, social support, and HIV-related behaviours. Participants with a high percentage of alters who were supportive of HIV testing were significantly more likely to have tested in the past six months (p = .02), and less likely to have engaged in unprotected anal intercourse (UAI) in the past three months (p = .003). Multivariate regression analyses of social network characteristics, and social support, revealed that testing in the past six months was significantly associated with social support for safer sex, instrumental social support, and age. Similarly, UAI in the past three months was significantly associated with social support for safer sex, homophily based on sexual identity and HIV status. HIV-related social support provided through the HBC networks was correlated with recent HIV testing and reduced UAI. Approaches utilising networks within alternative kinship systems, may increase HIV-related social support and improve HIV-related outcomes.

  9. African-American Biography.

    ERIC Educational Resources Information Center

    Martin, Ron

    1995-01-01

    Suggests sources of information for African American History Month for library media specialists who work with students in grades four through eight. Gale Research's "African-American Reference Library," which includes "African-America Biography,""African-American Chronology," and "African-American Almanac,"…

  10. Tackle-related injury rates and nature of injuries in South African Youth Week tournament rugby union players (under-13 to under-18): an observational cohort study

    PubMed Central

    Burger, Nicholas; Lambert, Mike I; Viljoen, Wayne; Brown, James C; Readhead, Clint; Hendricks, Sharief

    2014-01-01

    Objectives The tackle situation is most often associated with the high injury rates in rugby union. Tackle injury epidemiology in rugby union has previously been focused on senior cohorts but less is known about younger cohorts. The aim of this study was to report on the nature and rates of tackle-related injuries in South African youth rugby union players representing their provinces at national tournaments. Design Observational cohort study. Setting Four South African Youth Week tournaments (under-13 Craven Week, under-16 Grant Khomo Week, under-18 Academy Week, under-18 Craven Week). Participants Injury data were collected from 3652 youth rugby union players (population at risk) in 2011 and 2012. Outcome measures Tackle-related injury severity (‘time-loss’ and ‘medical attention’), type and location, injury rate per 1000 h (including 95% CIs). Injury rate ratios (IRR) were calculated and modelled using a Poisson regression. A χ2 analysis was used to detect linear trends between injuries and increasing match quarters. Results The 2012 under-13 Craven Week had a significantly greater ‘time-loss’ injury rate when compared with the 2012 under-18 Academy Week (IRR=4.43; 95% CI 2.13 to 9.21, p<0.05) and under-18 Craven Week (IRR=3.52; 95% CI 1.54 to 8.00, p<0.05). The Poisson regression also revealed a higher probability of ‘overall’ (‘time-loss’ and ‘medical attention’ combined) and ‘time-loss’ tackle-related injuries occurring at the under-13 Craven Week. The proportion of ‘overall’ and ‘time-loss’ injuries increased significantly with each quarter of the match when all four tournaments were combined (p<0.05). Conclusions There was a difference in the tackle-related injury rate between the under-13 tournament and the two under-18 tournaments, and the tackle-related injury rate was higher in the final quarter of matches. Ongoing injury surveillance is required to better interpret these findings. Injury prevention strategies

  11. HIV/AIDS prevention, faith, and spirituality among black/African American and Latino communities in the United States: strengthening scientific faith-based efforts to shift the course of the epidemic and reduce HIV-related health disparities.

    PubMed

    Sutton, Madeline Y; Parks, Carolyn P

    2013-06-01

    Black/African American and Latino communities are disproportionately affected by the domestic HIV/AIDS epidemic. Blacks/African Americans and Latinos are also more likely to report a formal, religious, or faith affiliation when compared with non-Hispanic whites. As such, faith leaders and their institutions have been identified in the National HIV/AIDS Strategy as having a vital role to serve in reducing: (1) HIV-related health disparities and (2) the number of new HIV infections by promoting non-judgmental support for persons living with and at risk for HIV/AIDS and by serving as trusted information resources for their congregants and communities. We describe faith doctrines and faith-science partnerships that are increasing in support of faith-based HIV prevention and service delivery activities and discuss the vital role of these faith-based efforts in highly affected black/African American and Latino communities.

  12. U.S. Professional Association Initiatives Related to Black South Africans: An Analysis and An Inventory. Information Exchange: Working Paper #2.

    ERIC Educational Resources Information Center

    Gottlieb, Julie D.

    The nature and level of activity among U.S. private sector groups seeking to expand educational opportunities for black South Africans is examined. The Information Exchange of the Institute of International Education (South African Programs) did research on such categories of organizations as foundations, church groups, educational institutions,…

  13. Intervention Induced Changes on Parenting Practices, Youth Self-Pride and Sexual Norms to Reduce HIV-Related Behaviors among Rural African American Youths

    ERIC Educational Resources Information Center

    Murry, Velma McBride; Berkel, Cady; Chen, Yi-fu; Brody, Gene H.; Gibbons, Frederick X.; Gerrard, Meg

    2011-01-01

    AIDS is the leading killer of African Americans between the ages of 25 and 44, many of whom became infected when they were teenagers or young adults. The disparity in HIV infection rate among African Americans youth residing in rural Southern regions of the United States suggests that there is an urgent need to identify ways to promote early…

  14. Higher Education in Africa. Hearing before the Subcommittee on African Affairs of the Committee on Foreign Relations, United States Senate, One Hundred Third Congress, First Session (May 17, 1993).

    ERIC Educational Resources Information Center

    Congress of the U.S., Washington, DC. Senate Committee on Foreign Relations.

    Testimony on federal aid to higher education in Africa is recorded in this report of a congressional hearing. Subcommittee chairman Senator Paul Simon opened by describing his hope that more U.S. aid be directed to the relatively new but now deteriorating African institutions of higher education. John Hicks, from the Bureau for Africa at the…

  15. Emotion-Oriented Coping, Avoidance Coping, and Fear of Pain as Mediators of the Relationship between Positive Affect, Negative Affect, and Pain-Related Distress among African American and Caucasian College Women

    ERIC Educational Resources Information Center

    Lightsey, Owen Richard, Jr.; Wells, Anita G.; Wang, Mei-Chuan; Pietruszka, Todd; Ciftci, Ayse; Stancil, Brett

    2009-01-01

    The authors tested whether coping styles and fear of pain mediate the relationship between positive affect and negative affect on one hand and pain-related distress (PD) on the other. Among African American and Caucasian female college students, negative affect, fear of pain, and emotion-oriented coping together accounted for 34% of the variance…

  16. African Trypanosomiasis

    DTIC Science & Technology

    2011-06-01

    infection by protozoan hemo- flagellates of the Trypanosoma brucei complex, 2 subspe- cies of which cause disease in humans: Trypanosoma bru- cei gambiense...public release; distribution unlimited 13. SUPPLEMENTARY NOTES See also ADA545141. Chapter 3 from e-book, Topics on the Pathology of Protozoan and...the brief ferry crossing. 2 3 • Topics on The paThology of proTozoan and invasive arThropod diseases Three severe epidemics of African trypanosomiasis

  17. Bioethics training programmes for Africa: evaluating professional and bioethics-related achievements of African trainees after a decade of Fogarty NIH investment

    PubMed Central

    Kass, Nancy E; Ali, Joseph; Hallez, Kristina

    2016-01-01

    Objectives Our primary aim was to evaluate the impact of US National Institutes of Health (NIH)-funded bioethics training programmes (Fogarty bioethics training programmes, FBTPs) that trained individuals from Africa over the programme's first 10 years to examine changes between pretraining and post-training in individual achievement and to document any associations between individual, training programme and post-training accomplishments. Design We surveyed trainees from the 10 bioethics programmes funded by NIH Fogarty International Center from 2000 to 2011 that included African trainees. McNemar's and Wilcoxon signed rank-sum tests were used to analyse pre–post levels of general and bioethics-related professional achievement. Likelihood of specific post-training achievement outcomes was measured using logistic regression including demographic, pretraining and intratraining variables. Setting 10 different FBTPs that trained individuals from Africa from 2000 to 2011. Participants Of 253 eligible respondents, 171 completed the survey (response rate 67.6%). Primary outcome measures Pre–post comparisons of professional achievement indicators (eg, serving in leadership roles, teaching, publishing manuscripts); likelihood of specific post-training achievement outcomes. Results Post-training, respondents were significantly more likely to report serving in a leadership role, being an investigator on a research grant, serving on international committees, serving as a mentor, and publishing manuscripts than at pretraining. Post-training, significantly greater numbers of respondents reported bioethics-related achievements including being a bioethics instructor, serving on an Institutional Review Board (IRB), being an investigator on a bioethics grant and publishing bioethics-related manuscripts than pretraining. Controlling for other factors, there were no significant differences by gender in the post-training success of these participants in terms of leadership roles

  18. Nappes, tectonics of oblique plate convergence, and metamorphic evolution related to 140 million years of continuous subduction, Franciscan Complex, California

    SciTech Connect

    Wakabayashi, J. )

    1992-01-01

    This paper presents a new synthesis of Franciscan Complex tectonics, with the emphasis on the pre-San Andreas fault history of these rocks. Field relations suggest that the Franciscan is characterized by nappe structures that formed during sequential accretion at the trench. The presence of these structures along with other field relations, including the lack of evidence for large offset of conglomerate suites, indicates that strike-slip fault systems of large displacement ({gt}500 km) did not cut the Franciscan Complex during subduction. Regional geology and comparisons to modern arc-trench systems suggest that strike-slip faulting associated with oblique subduction took place inboard (east) of the Franciscan in the vicinity of the magmatic arc. The Franciscan varies along strike, because individual accreted elements (packets of trench sediment, seamounts, etc.) did not extend the full length of the trench. Different depths of underplating, distribution of post-metamorphic faulting, and level of erosion produced the present-day surface distribution of high P/T metamorphism. Franciscan Complex tectonic history is presented in this paper.

  19. A new velocity field for Africa from combined GPS and DORIS space geodetic Solutions: Contribution to the definition of the African reference frame (AFREF)

    NASA Astrophysics Data System (ADS)

    Saria, E.; Calais, E.; Altamimi, Z.; Willis, P.; Farah, H.

    2013-04-01

    We analyzed 16 years of GPS and 17 years of Doppler orbitography and radiopositioning integrated by satellite (DORIS) data at continuously operating geodetic sites in Africa and surroundings to describe the present-day kinematics of the Nubian and Somalian plates and constrain relative motions across the East African Rift. The resulting velocity field describes horizontal and vertical motion at 133 GPS sites and 9 DORIS sites. Horizontal velocities at sites located on stable Nubia fit a single plate model with a weighted root mean square residual of 0.6 mm/yr (maximum residual 1 mm/yr), an upper bound for plate-wide motions and for regional-scale deformation in the seismically active southern Africa and Cameroon volcanic line. We confirm significant southward motion ( ˜ 1.5 mm/yr) in Morocco with respect to Nubia, consistent with earlier findings. We propose an updated angular velocity for the divergence between Nubia and Somalia, which provides the kinematic boundary conditions to rifting in East Africa. We update a plate motion model for the East African Rift and revise the counterclockwise rotation of the Victoria plate and clockwise rotation of the Rovuma plate with respect to Nubia. Vertical velocities range from - 2 to +2 mm/yr, close to their uncertainties, with no clear geographic pattern. This study provides the first continent-wide position/velocity solution for Africa, expressed in International Terrestrial Reference Frame (ITRF2008), a contribution to the upcoming African Reference Frame (AFREF). Except for a few regions, the African continent remains largely under-sampled by continuous space geodetic data. Efforts are needed to augment the geodetic infrastructure and openly share existing data sets so that the objectives of AFREF can be fully reached.

  20. Associations between HIV-related stigma, racial discrimination, gender discrimination, and depression among HIV-positive African, Caribbean, and Black women in Ontario, Canada.

    PubMed

    Logie, Carmen; James, Llana; Tharao, Wangari; Loutfy, Mona

    2013-02-01

    Abstract African, Caribbean, and Black (ACB) women are greatly overrepresented in new HIV infections in comparison with Canada's general population. Social and structural factors such as HIV-related stigma, gender discrimination, and racial discrimination converge to increase vulnerability to HIV infection among ACB women by reducing access to HIV prevention services. Stigma and discrimination also present barriers to treatment, care, and support and may contribute to mental health problems. We administered a cross-sectional survey to HIV-positive ACB women (n=173) across Ontario in order to examine the relationships between HIV-related stigma, gender discrimination, racial discrimination, and depression. One-third of participants reported moderate/severe depression scores using the Beck Depression Inventory Fast-Screen guidelines. Hierarchical block regression, moderation, and mediation analyses were conducted to measure associations between independent (HIV-related stigma, gender discrimination, racial discrimination), moderator/mediator (social support, resilient coping), and dependent (depression) variables. Findings included: (1) HIV-related stigma was associated with increased depression; (2) resilient coping was associated with reduced depression but did not moderate the influence of HIV-related stigma on depression; and (3) the effects of HIV-related stigma on depression were partially mediated through resilient coping. HIV-related stigma, gender discrimination, and racial discrimination were significantly correlated with one another and with depression, highlighting the salience of examining multiple intersecting forms of stigma. Generalizability of findings may be limited due to nonrandom sampling. Findings emphasize the importance of multi-component interventions, including building resilient coping skills, mental health promotion and assessment, and stigma reduction programs.

  1. Wild Termitomyces Species Collected from Ondo and Ekiti States Are More Related to African Species as Revealed by ITS Region of rDNA

    PubMed Central

    Oyetayo, Victor Olusegun

    2012-01-01

    Molecular identification of eighteen Termitomyces species collected from two states, Ondo and Ekiti in Nigeria was carried out using the internal transcribed spacer (ITS) region. The amplicons obtained from rDNA of Termitomyces species were compared with existing sequences in the NCBI GenBank. The results of the ITS sequence analysis discriminated between all the Termitomyces species (obtained from Ondo and Ekiti States) and Termitomyces sp. sequences obtained from NCBI GenBank. The degree of similarity of T1 to T18 to gene of Termitomyces sp. obtained from NCBI ranges between 82 and 99 percent. Termitomyces species from Garbon with ascension number AF321374 was the closest relative of T1 to T18 except T12 that has T. eurhizus and T. striatus as the closet relative. Phylogenetic tree generated with ITS sequences obtained from NCBI GenBank data revealed that T1 to T18 are more related to Termitomyces species indigenous to African countries such as Senegal, Congo, and Gabon. PMID:22649309

  2. Relative influence of surficial, climatic, and plate tectonic processes on the development of thick Paleoproterozoic quartz arenite successions

    NASA Astrophysics Data System (ADS)

    Corcoran, P.; Bynoe, L.

    2010-12-01

    Quartz arenites are significant components of the rock record and appear to be most abundant during specific time intervals in Earth history. Thick quartz arenite successions are typical in Precambrian strata and have been associated with extensive cratonization during the late Archean to early Proterozoic. These supermature sandstones can also be attributed to the intense weathering conditions of early Earth’s atmosphere, source rocks rich in quartz, recycling and diagenesis, or simply the higher preservation potential of quartz compared with other minerals. Modern quartz-rich sands develop in low relief settings where high residence times contribute to chemical breakdown of labile grains. The lack of land vegetation during the Precambrian would have precluded confined sedimentation patterns and stabilization of soils, both of which enhance sediment residence times. Thus, the generation of first-cycle late Archean quartz arenites in fault-controlled, high relief basins necessitates periods of intense chemical weathering. The inferred change from a greenhouse to oxygenated atmosphere at around 2.3-2.2 Ga could have been the major control on the relative change to thinner units of pure sandstones with time. In order to test this hypothesis, detailed facies and compositional analyses are being conducted on the ca. 2.2 Ga Bar River Formation of the Huronian Supergroup, Canada. Four groups comprise Huronian stratigraphy, three of which contain basal glaciogenic conglomerates, followed by mudstone-dominated then quartz-rich formations. It has been suggested that these tripartite cycles could have been climatically controlled. Detailed facies analysis of the 500-750 m thick quartz arenite indicates shallow water, wave-influenced settings, akin to shoreface environments along extensive stable shelves. Thin mudstone interbeds, representing brief periods of suspension sedimentation, have been sampled for geochemical analysis in order to determine the degree of chemical

  3. Structure and breakup history of the rifted margin of West Antarctica in relation to Cretaceous separation from Zealandia and Bellingshausen plate motion

    NASA Astrophysics Data System (ADS)

    Wobbe, F.; Gohl, K.; Chambord, A.; Sutherland, R.

    2012-04-01

    Geophysical data acquired using R/V Polarstern constrain the structure and age of the rifted oceanic margin of West Antarctica. West of the Antipodes Fracture Zone, the 145 km wide continent-ocean transition zone (COTZ) of the Marie Byrd Land sector resembles a typical magma-poor margin. New gravity and seismic reflection data indicates initial continental crust of thickness 24 km, that was stretched 90 km. Farther east, the Bellingshausen sector is broad and complex with abundant evidence for volcanism, the COTZ is ˜670 km wide, and the nature of crust within the COTZ is uncertain. Margin extension is estimated to be 106-304 km in this sector. Seafloor magnetic anomalies adjacent to Marie Byrd Land near the Pahemo Fracture Zone indicate full-spreading rate during c33-c31 (80-68 Myr) of 60 mm yr-1, increasing to 74 mm yr-1 at c27 (62 Myr), and then dropping to 22 mm yr-1 by c22 (50 Myr). Spreading rates were lower to the west. Extrapolation towards the continental margin indicates initial oceanic crust formation at around c34y (84 Myr). Subsequent motion of the Bellingshausen plate relative to Antarctica (84-62 Myr) took place east of the Antipodes Fracture Zone at rates <40 mm yr-1, typically 5-20 mm yr-1. The high extension rate of 30-60 mm yr-1 during initial margin formation is consistent with steep and symmetrical margin morphology, but subsequent motion of the Bellingshausen plate was slow and complex, and modified rift morphology through migrating deformation and volcanic centers to create a broad and complex COTZ.

  4. Fracture severity of distal radius fractures treated with locking plating correlates with limitations in ulnar abduction and inferior health-related quality of life

    PubMed Central

    Tsitsilonis, Serafim; Machó, David; Manegold, Sebastian; Krapohl, Björn Dirk; Wichlas, Florian

    2016-01-01

    Introduction/background: The operative treatment of distal radius fractures has significantly increased after the introduction of locking plates. The aim of the present study was the evaluation of health-related quality of life, functional and radiological outcome of patients with distal radius fractures treated with the locking compression plate (LCP). Materials and methods: In the present study 128 patients (130 fractures) that were operatively treated with the LCP (2.4 mm/3.5 mm, Synthes®) were retrospectively evaluated. Mean follow-up was 22.7 months (SD 10.6). The fractures were radiographically evaluated (radial inclination, palmar tilt, ulnar variance) pre-, postoperatively and at the last follow-up visit. Range of motion (ROM) was documented. Grip strength was assessed with the use of a JAMAR dynamometer. The score for disabilities of the arm, shoulder and hand (DASH) and the Gartland-Werley score (GWS) were evaluated. Health-associated quality of life was assessed with use of SF-36 Health Survey. Results: Postoperative reduction was excellent; at the last follow-up visit only minimal reduction loss was observed. Except for pronation, a statistically significant decrease of ROM was present; in most cases that was not disturbing for the patients. The injured side achieved 83.9% of grip strength of the intact side. Mean DASH was 18.9 and mean GWS was 3.5. Health-associated quality of life was generally not compromised. However, limitations in ulnar abduction correlated with inferior quality of life. Fracture severity correlated with inferior quality of life, despite the absence of correlation with the functional and radiological outcome. Complication rate was low. Conclusions: Fracture severity seems to affect ulnar abduction and therefore patient quality of life, despite almost anatomical reduction; the objective and subjective scores were in most cases excellent. Modern everyday activities, such as keyboard typing, could be associated with the present

  5. Expression of cell adhesion and differentiation related genes in MC3T3 osteoblasts plated on titanium alloys: role of surface properties.

    PubMed

    Sista, Subhash; Wen, Cuie; Hodgson, Peter D; Pande, Gopal

    2013-04-01

    It is important to understand the cellular and molecular events that take place at the cell-material interface of implants used for bone repair. An understanding of the mechanisms involved in the initial stages of osteoblast interactions with the surface of the implant material is fundamental in deciding the fate of the cells that come in contact with it. In this study, we compared the relative gene expression of markers that are known to be associated with cell adhesion and differentiation in MC3T3 osteoblast cells, at various time points after plating the cells on surfaces of titanium (Ti) and its two alloys, titanium-zirconium (TiZr) and titanium-niobium (TiNb) by using Quantitative Real Time Polymerase Chain Reaction (RT-PCR). Our analysis indicated that expression of adhesion supporting genes was higher on TiZr surface as compared to Ti and TiNb. The behavior of these genes is possibly driven by a higher surface energy of TiZr. However no significant difference in the expression of differentiation related genes could be seen between the two alloys, although on both substrates it was higher as compared to unalloyed Ti. We propose that substrate composition of the alloys can influence the adhesion and differentiation related gene expression and that Ti alloys are better substrates for inducing osteogenesis as compared to unalloyed Ti.

  6. Formation and metasomatism of continental lithospheric mantle in intra-plate and subduction-related tectonic settings

    NASA Astrophysics Data System (ADS)

    Ionov, Dmitri

    2010-05-01

    Our knowledge of the origin and evolution of the continental lithospheric mantle (CLM) remains fragmentary and partly controversial in spite of recent advances in petrologic, geochemical and geophysical studies of the deep Earth and experimental work. Debate continues on a number of essential topics, like relative contributions of partial melting, metasomatism and ‘re-fertilisation' as well as the timing, conditions and tectonic settings of those processes. These topics can be addressed by studies of ultramafic xenoliths in volcanic rocks which arguably provide the least altered samples of modern and ancient CLM. The subcontinental lithosphere is thought to be a mantle region from which melts have been extracted, thus making the lithosphere more refractory. Melting degrees can be estimated from Al contents while the depth of melt extraction can be assessed from Al-Fe (Mg#) relations in unmetasomatized melting residues in comparison with experimental data, e.g. [1]. High silica and opx in the residues may indicate melting in water-rich conditions. High-precision Mg# and Mn for olivine may constrain degrees and conditions of partial melting and/or metasomatism, tectonic settings, modal compositions (e.g. presence of garnet) and equilibration conditions of mantle peridotites [2]. These estimates require both adequate sampling and high-quality major element and modal data; sampling and analytical uncertainties in published work may contribute substantially to chemical heterogeneities (and different origins) inferred for CLM domains [3]. Very fertile peridotite xenolith suites are rare worldwide [3]. They were initially viewed as representing mantle domains that experienced only very small degrees of melt extraction but are attributed by some workers to ‘refertilization' of refractory mantle by percolating asthenospheric melts. Such alternative mechanisms might be valid for some rare hybrid and Fe-enriched peridotites but they fail to comprehensively explain modal

  7. Balancing truth-telling: relatives acting as translators for older adult cancer patients of Turkish or northwest African origin in Belgium.

    PubMed

    van Eechoud, I; Grypdonck, M; Leman, J; Van Den Noortgate, N; Deveugele, M; Verhaeghe, S

    2016-05-01

    The first generation of Turkish and Northwest African immigrants in Belgium are ageing and at risk for developing cancer. Relatives play an important role and provide both emotional and practical care, including mental support and acting as a contact person and/or a translator for improving access to healthcare, as most patients and their spouses have only a limited command of the language. Although access to professional interpreters has shown to be the best guarantee for qualitative healthcare, oncology health providers working with relatives as interpreters is much more common than professional interpreters. The aim of this study was to provide insight into the process wherein relatives balance truth-telling in translating for an older family member diagnosed with cancer. This was a qualitative research study, with elements of constructivist grounded theory. Twenty-eight loosely structured interviews were conducted. Most relatives consider it their responsibility to contribute to a positive attitude of the patient. Relatives decided to what extent they inform the patient, based on several motives and embedded in their assessment of the patient's emotional strength, understanding and need to be informed. What they decide influences the way they act as a translator and/or a contact person between the patient and health professional(s). Some considered it best to omit medical information while others considered it best to inform the patient fully. The results emphasise the importance for healthcare providers to take into account the complexity and unpredictable character of the process of balancing truth-telling when family members translate for their ill older relative.

  8. Image and Reality in African Interethnic Relations: The Fulbe and Their Neighbors. Studies in Third World Societies, Publication Number Eleven.

    ERIC Educational Resources Information Center

    Schultz, Emily A., Ed.

    The eight articles in this collection focus on the Fulbe culture in West Africa, its intragroup relationships as well as its relations with other ethnic groups. Each article relates the concept of ethnicity to social and political differentiation among tribes. Following an introduction by Emily Schultz, John Lewis presents the findings of three…

  9. Relation between the Supplemental Nutritional Assistance Program cycle and dietary quality in low-income African Americans in Baltimore, Maryland123

    PubMed Central

    Kharmats, Anna Y; Jones-Smith, Jessica C; Cheah, Yun Sang; Budd, Nadine; Flamm, Laura; Cuccia, Alison; Mui, Yeeli; Trude, Angela; Gittelsohn, Joel

    2014-01-01

    Background: There has been limited research regarding the Supplemental Nutritional Assistance Program (SNAP) and recipients’ dietary quality during the days and weeks after benefit disbursement. Objective: We examined the relation between participants’ stages in the SNAP cycle and their macronutrient consumption, Healthy Eating Index (HEI) scores, and fruit and vegetable intake. Design: In this cross-sectional study, we analyzed single 24-h dietary recalls collected from 244 African American SNAP participants recruited near 24 corner stores in Baltimore City. A multiple linear regression analysis and bootstrapping were used. Results: Among participants who received a SNAP benefit ≤15 d before being surveyed, energy intake adjusted for minimum energy requirements (−4.49%; 95% CI: −8.77%, −0.15%) and HEI dairy scores (−0.12; 95% CI: −0.22, −0.01) were lower for each 1-d increase in the time since SNAP distribution (TSSD). Among participants who received SNAP benefits >15 d before being surveyed, energy intake (1.35%; 95% CI: 0.01%, 2.73%), energy intake adjusted for minimum energy requirements (3.86%; 95% CI: 0.06%, 7.96%), total fat intake (1.96%; 95% CI: 0.29%, 3.8%), saturated fat intake (2.02%; 95% CI: 0.23%, 4.01%), and protein intake (2.09%; 95% CI: 0.70%, 3.62%) were higher per each 1-d increase in the TSSD. Conclusions: These findings suggest that the relation between the TSSD and macronutrient intake might be U-shaped, with higher intake of calories, fat, and protein in individuals in the very early and late stages of their SNAP cycles. Foods high in these nutrients might be cheaper, more accessible, and have a longer shelf-life than healthier options, such as fruit, vegetables, and whole grains, for SNAP participants when their benefits run out. Additional efforts are needed to investigate the effect of the TSSD on dietary intake by using a longitudinal design and to improve the quality of dietary intake in African American SNAP

  10. A New Absolute Plate Motion Model for Africa

    NASA Astrophysics Data System (ADS)

    Maher, S. M.; Wessel, P.; Müller, D.; Harada, Y.

    2013-12-01

    The India-Eurasia collision, a change in relative plate motion between Australia and Antarctica, and the coeval ages of the Hawaiian Emperor Bend (HEB) and Louisville Bend of ~Chron 22-21 all provide convincing evidence of a global tectonic plate reorganization at ~50 Ma. Yet if it were a truly global event, then there should be a contemporaneous change in Africa absolute plate motion (APM) reflected by physical evidence somewhere on the Africa plate. This evidence might be visible in the Reunion-Mascarene bend, which exhibits many HEB-like features such as a large angular change close to ~50 Ma. Recently, the Reunion hotpot trail has been interpreted as a continental feature with incidental hotspot volcanism. Here we propose the alternative hypothesis that the northern portion of the chain between Saya de Malha and the Seychelles (Mascarene Plateau) formed as the Reunion hotspot was situated on the Carlsberg Ridge, contemporaneously forming the Chagos-Laccadive Ridge on the India plate. We have created a 4-stage model that explores how a simple APM model fitting the Mascarene Plateau can also satisfy the age progressions and geometry of other hotspot trails on the Africa plate. This type of model could explain the apparent bifurcation of the Tristan hotspot chain, the age reversals seen along the Walvis Ridge and the diffuse nature of the St. Helena chain. To test this hypothesis we have made a new African APM model that goes back to ~80 Ma using a modified version of the Hybrid Polygonal Finite Rotation Method. This method uses seamount chains and their associated hotspots as geometric constraints for the model, and seamount age dates to determine its motion through time. The positions of the hotspots can be moved to get the best fit for the model and to explore the possibility that the ~50 Ma bend in the Reunion-Mascarene chain reflects Africa plate motion. We will examine how well this model can predict the key features reflecting Africa plate motion and

  11. Forming Weld Lands On Metal Plates

    NASA Technical Reports Server (NTRS)

    Weddendorf, Bruce

    1994-01-01

    Forming shoe pounds edge of newly inserted plate workpiece. After many passes of shoe and advances of plate, thick land builds up at edge. Workpiece heated to enable metal to flow without strain hardening. Proposed upset-forming process replaces relatively expensive, time-consuming, and wasteful process in which integral weld lands created by machining metal away from plates everywhere except at lands.

  12. Recent plate motions and crustal deformation

    SciTech Connect

    Lisowski, M. )

    1991-01-01

    Reports by U.S. workers on geodetic measurements of recent plate motions or crustal deformation published in 1987-1990 are reviewed. The review begins with global plate motions, proceeds through plate boundaries in California, Alaska, and the Pacific Northwest, and finishes with volcanic phenomena, monument stability and longevity, and GPS relative position measurements. 184 refs.

  13. High-resolution modelling and error analysis of late-Cenozoic African topography driven by mantle convection

    NASA Astrophysics Data System (ADS)

    Moucha, R.; Forte, A. M.; Rowley, D. B.; Mitrovica, J.; Simmons, N. A.; Grand, S. P.; Glisovic, P.

    2010-12-01

    An outstanding problem in African continental dynamics is the delineation of the mantle convective flow below the African plate and its relationship to the evolution of continental topography. Over the last decade numerous studies have focused on modelling the present-day African dynamic topography using seismic-tomography based mantle convection simulations (e.g. Lithgow-Bertolini et al., 1998; Gurnis et al., 2000; Daradich et al., 2003; Forte et al., 2010). However, the majority of these investigations of tomography-based convection below Africa have been based on long wavelength global tomography models, which resolve structures with scale lengths generally in excess of 1000 km. This spatial resolution is insufficient for mapping out a detailed connection between the surface manifestations of African hotspot magmatism, topographic anomalies and the sublithospheric mantle flow pattern below the African plate. Substantial progress has recently been made in deriving a seismic tomography model which approaches the horizontal resolution needed to address these modelling challenges (e.g. Simmons et al., 2009). This tomography model provides explicit estimates of both thermal and chemical contributions to mantle buoyancy and we employ it in a mantle convection simulation that satisfies the combined set of geodynamic constraints related to the present-day surface gravity and topography anomalies. Utilizing this present-day geodynamic model we reconstruct the late Cenozoic dynamic topography of Africa by carrying out backward-in-time mantle flow simulations. Uncertainties in our reconstruction of topography that originate from the starting models of mantle heterogeneity, rheology and different plate reconstructions are fully investigated and compared with the geological record. The consideration of such uncertainties was usually ignored in previous studies, but we demonstrate their importance in evaluating the robustness of the time-dependent topography reconstructions

  14. Present-day plate motions

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1977-01-01

    A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

  15. Depressive Symptoms Are More Strongly Related to Executive Functioning and Episodic Memory Among African American compared with Non-Hispanic White Older Adults

    PubMed Central

    Zahodne, Laura B.; Nowinski, Cindy J.; Gershon, Richard C.; Manly, Jennifer J.

    2014-01-01

    We examined whether the reserve capacity model can be extended to cognitive outcomes among older African Americans. Two hundred and ninety-two non-Hispanic Whites and 37 African Americans over age 54 participated in the normative study for the NIH Toolbox for the Assessment of Neurological and Behavioral Function. Multiple-group path analysis showed that associations between depressive symptoms and cognition differed by race, independent of age, education, reading level, income, health, and recruitment site. Depressive symptoms were associated with slowed processing speed among Whites and worse task-switching, inhibition, and episodic memory among African Americans. African Americans may be more vulnerable to negative effects of depression on cognition than non-Hispanic Whites. Further research is needed to explicate the psychological and neurobiological underpinnings of this greater vulnerability. PMID:25280795

  16. Polymorphism of the human factor H-related gene (FHR-1) and of factor H in a West African individual

    SciTech Connect

    Meyer, C.G.; Skerka, C.; Zipfel, P.F.

    1995-03-01

    The human factor H-related 1 (FHR-1) protein is structurally and immunogenically related to the regulatory complement protein factor H (FH). Polymorphism of the FHR-1 gene is indicated by the nucleotide differences as described by the five cDNA clones isolated so far. In order to further analyze this polymorphism we identified PCR-primers which allow the simultaneous amplification of FHR-1 and FH alleles in a single polymerase chain reaction (PCR). By DNA sequence analysis, two novel FHR-1 variants and one as yet unrecognized FH allele could be characterized in an individual from Benin, West Africa. 2 refs., 1 fig.

  17. Challenging empowerment: AIDS-affected South African children and the need for a multi-level relational approach.

    PubMed

    Ansell, Nicola

    2014-01-01

    Critics of empowerment have highlighted the concept's mutability, focus on individual transformation, one-dimensionality and challenges of operationalisation. Relating these critiques to children's empowerment raises new challenges. Drawing on scholarship on children's subjecthood and exercise of power, alongside empirical research with children affected by AIDS, I argue that empowerment envisaged as individual self-transformation and increased capacity to act independently offers little basis for progressive change. Rather it is essential to adopt a relational approach that recognises the need to transform power relationships at multiple levels. This analysis has implications for our wider understanding of empowerment in the 21st century.

  18. Violence Exposure and Health-Related Risk among African American Adolescent Female Detainees: A Strategy for Reducing Recidivism

    ERIC Educational Resources Information Center

    Woodson, Kamilah M.; Hives, Courtney C.; Sanders-Phillips, Kathy

    2010-01-01

    Juvenile crime and violent victimization continue to be significant social problems, in that adolescents, females in particular, are likely to participate in health-related risk behaviors as a result of having been victimized or exposed to a violent environment. Specifically, abuse, neglect, sexual molestation, poverty, and witnessing violence are…

  19. How Are the Mathematical Identities of Low Achieving South African Eleventh Graders Related to Their Ability to Solve Mathematical Tasks?

    ERIC Educational Resources Information Center

    Cranfield, Corvell

    2013-01-01

    The construct of mathematical identity has recently been widely used in mathematics education with the intention to understand how students relate to and engage (or disengage) with mathematics. Grootenboer and Zevenbergen (2008) define mathematical identity as the students' knowledge, abilities, skills, beliefs, dispositions, attitudes and…

  20. A prospective epidemiological study on odontogenic tumours in a black African population, with emphasis on the relative frequency of ameloblastoma.

    PubMed

    Oginni, F O; Stoelinga, P J W; Ajike, S A; Obuekwe, O N; Olokun, B Aluko; Adebola, R A; Adeyemo, W L; Fasola, O; Adesina, O A; Akinbami, B O; Iwegbu, I O; Ogunmuyiwa, S A; Obimakinde, O S; Uguru, C C

    2015-09-01

    The persistent view in the literature is that the relative frequency of ameloblastomas is higher in the black population than in Caucasians. The aim of this study was to determine the relative frequency of all odontogenic tumours (OT) in a 100% black population and to compare our findings with those of previous studies. A prospective study was undertaken of all patients presenting with OT to all 16 Nigerian departments of oral and maxillofacial surgery over a 4-year period. The following data were obtained: patient demographics, delay to presentation, extent of the lesion, and histological diagnosis. Six hundred and twenty-two cases were studied. A slight male preponderance was observed (male to female ratio 1.17:1). Patients ranged in age from 5 to 89 years, with a peak incidence in the third decade. The relative frequency of OT was 0.99 per million and that of ameloblastoma was 0.76 per million. Ameloblastoma was the most prevalent OT (76.5%), followed by adenomatoid odontogenic tumours (5.6%), odontogenic myxoma (4.5%), and keratocystic odontogenic tumours (KCOT) (3.1%). The relative frequency of ameloblastoma among Nigerians was not different from frequencies reported previously among Caucasian and Tanzanian black populations. KCOTs were, however, rarely diagnosed in Nigerians as compared to the white population in the Western world.

  1. Intermittent Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Silver, P. G.; Behn, M. D.

    2006-12-01

    Intermittent Plate Tectonics A basic premise of Earth Science is that plate tectonics has been continuously operating since it began early in Earth's history. Yet, plate-tectonic theory itself, specifically the collisional phase of the Wilson Cycle, constitutes a process that is capable of stopping all plate motion. The plausibility of a plate-tectonic hiatus is most easily illustrated by considering the expected future of the present-day plate-tectonic configuration. Since the opening of the Atlantic at ~200 ma, the area of the Atlantic basin has been growing at the expense of the Pacific. If this trend continues, relative plate motion models predict that in ~350 my, the Pacific Ocean basin will effectively close leading to widespread continent-continent collisions. Since a continent-continent collision represents the termination of subduction locally, the accumulated effect of all collisions is to stop subduction globally. In this scenario, ridges would then stop spreading and young oceanic lithosphere would cool, reaching a steady-state thickness of 100 km in about 80 my, based on the properties of oceanic lithosphere today. This would constitute the stoppage of plate tectonics. The presumption that plate tectonics never stops in the face of continental collisions is equivalent to requiring that subduction flux is approximately constant through time, such that subduction initiation roughly balances subduction termination. Such a balance then raises several questions about the subduction initiation process. When and how does subduction initiate? Is there a detectible relationship between subduction cessation and subduction initiation? We can gain some guidance into these questions by examining the plate motion history over the last 200 my. Subduction initiation has occurred over the last 80 my in three intra- oceanic subduction zones: Aleutians, Marianas-Izu-Bonin and Tonga-Kermadec in the Pacific basin. In these cases, however, subduction initiation would not

  2. Evaluation of the Interplate and Intraplate Deformations of the African Continent Using cGNSS Data

    NASA Astrophysics Data System (ADS)

    Apolinário, J. P.; Fernandes, R. M. S.; Bos, M. S.; Meghraoui, M.; Miranda, J. M. A.

    2014-12-01

    Two main plates, Nubia and Somalia, plus some few more tectonic blocks in the East African Rift System (EARS) delimit the African continent. The major part of the external plate boundaries of Africa is well defined by oceanic ridge systems with the exception of the Nubia-Eurasia complex convergence-collision tectonic zone. In addition, the number and distribution of the tectonic blocks along the EARS region is a major scientific issue that has not been completely answered so far. Nevertheless, the increased number of cGNSS (continuous Global Navigation Satellite Systems) stations in Africa with sufficient long data span is helping to better understand and constrain the complex sub-plate distribution in the EARS as well as in the other plate boundaries of Africa. This work is the geodetic contribution for the IGCP-Project 601 - "Seismotectonics and Seismic Hazards in Africa". It presents the current tectonic relative motions of the African continent based on the analysis of the estimated velocity field derived from the existing network of cGNSS stations in Africa and bordering plate tectonics. For the majority of the plate pairs, we present the most recent estimation of their relative velocity using a dedicated processing. The velocity solutions are computed using HECTOR, a software that takes into account the existing temporal correlations between the daily solutions of the stations. It allows to properly estimate the velocity uncertainties and to detect any artifacts in the time-series. For some of the plate pairs, we compare our solutions of the angular velocities with other geodetic and geophysical models. In addition, we also study the sensitivity of the derived angular velocity to changes in the data (longer data-span for some stations) for tectonic units with few stations, and in particular for the Victoria and Rovuma blocks of the EARS. Finally, we compute estimates of velocity fields for several sub-regions correlated with the seismotectonic provinces and

  3. Understanding traditional African healing

    PubMed Central

    MOKGOBI, M.G.

    2015-01-01

    Traditional African healing has been in existence for many centuries yet many people still seem not to understand how it relates to God and religion/spirituality. Some people seem to believe that traditional healers worship the ancestors and not God. It is therefore the aim of this paper to clarify this relationship by discussing a chain of communication between the worshipers and the Almighty God. Other aspects of traditional healing namely types of traditional healers, training of traditional healers as well as the role of traditional healers in their communities are discussed. In conclusion, the services of traditional healers go far beyond the uses of herbs for physical illnesses. Traditional healers serve many roles which include but not limited to custodians of the traditional African religion and customs, educators about culture, counselors, social workers and psychologists. PMID:26594664

  4. Adolescent experiences of violence and relation to violence perpetration beyond young adulthood among an urban sample of Black and African American males.

    PubMed

    Reed, Elizabeth; Lawrence, Danielle A; Santana, M C; Welles, C Seth L; Horsburgh, C Robert; Silverman, Jay G; Rich, John A; Raj, Anita

    2014-02-01

    The purpose of this study is to determine if experiences of physical violence during early and late adolescence (12-21 years) places urban Black males at increased risk for interpersonal violence perpetration beyond young adulthood (30 years and older). Participants of this cross-sectional study were Black and African American men (N = 455) between the ages of 30 and 65 years, recruited from four urban clinical sites in the Northeast. Multivariate logistic regression models were used to analyze the relation of adolescent experiences of violence to: (1) past 6 month street violence involvement and (2) past year intimate partner violence perpetration. Ten percent of the sample reported that they experienced adolescent victimization. Men reporting adolescent victimization were significantly more likely to report past 6-month street violence involvement (Adjusted Odds Ratio (AOR) = 3.2, 95 % CI = 1.7-6.3) and past 6 month intimate partner violence perpetration (AOR = 2.8, 95 % CI = 1.8-5.4) compared to men who did not report such victimization. Study findings suggest that in order to prevent adulthood perpetration of violence, more work is needed to address experiences of victimization among young Black males, particularly violence experienced during adolescence.

  5. Elastic plate spallation

    NASA Technical Reports Server (NTRS)

    Oline, L.; Medaglia, J.

    1972-01-01

    The dynamic finite element method was used to investigate elastic stress waves in a plate. Strain displacement and stress strain relations are discussed along with the stiffness and mass matrix. The results of studying point load, and distributed load over small, intermediate, and large radii are reported. The derivation of finite element matrices, and the derivation of lumped and consistent matrices for one dimensional problems with Laplace transfer solutions are included. The computer program JMMSPALL is also included.

  6. Plume and plate controlled hotspot trails in the South Atlantic

    NASA Astrophysics Data System (ADS)

    O'Connor, John; Jokat, Wilfried; le Roex, Anton; Class, Cornelia; Wijbrans, Jan; Keßling, Stefanie; Kuiper, Klaudia; Nebel, Oliver

    2013-04-01

    Discovering if hotspots observed on the Earth's surface are explained by underlying plumes rising from the deep mantle or by shallow plate-driven processes continues to be an essential goal in Earth Science. Key evidence underpinning the mantle plume concept is the existence of age-progressive volcanic trails recording past plate motion relative to surface hotspots and their causal plumes. Using the icebreaker RV Polarstern, we sampled scattered hotspot trails on the 2,000 km-wide southeast Atlantic hotspot swell, which projects down to one of the Earth's two largest and deepest regions of slower-than-average seismic wave speed - the Africa Low Shear Wave Velocity Province - caused by a massive thermo-chemical 'pile' on the core-mantle boundary. We showed recently using Ar/Ar isotopic ages - and crustal structure and seafloor ages - that these hotspot trails are age progressive and formed synchronously across the swell, consistent with African plate motion over plumes rising from the stable edge of a Low Shear Wave Velocity Province (LLSVP) (O'Connor et al., 2012). We showed furthermore that hotspot trails formed initially only at spreading boundaries at the outer edges of the swell until roughly 44 million years ago, when they started forming across the swell, far from spreading boundaries in lithosphere that was sufficiently weak (young) for plume melts to reach the surface. We concluded that if plume melts formed synchronous age progressive hotspot trails whenever they could penetrate the lithosphere, then hotspot trails in the South Atlantic are controlled by the interplay between deep plumes and the shallow motion and structure of the African plate. If the distribution of hotspot trails reflects where plume melts could or could not penetrate the continental or oceanic lithosphere then plumes could have been active for significantly longer than indicated by their volcanic chains. This provides a mechanism for extended late stage interplay between deep mantle

  7. A deletion variant of the alpha2b-adrenoceptor is related to emotional memory in Europeans and Africans.

    PubMed

    de Quervain, Dominique J-F; Kolassa, Iris-Tatjana; Ertl, Verena; Onyut, P Lamaro; Neuner, Frank; Elbert, Thomas; Papassotiropoulos, Andreas

    2007-09-01

    Emotionally arousing events are recalled better than neutral events. This phenomenon, which helps us to remember important and potentially vital information, depends on the activation of noradrenergic transmission in the brain. Here we show that a deletion variant of ADRA2B, the gene encoding the alpha2b-adrenergic receptor, is related to enhanced emotional memory in healthy Swiss subjects and in survivors of the Rwandan civil war who experienced highly aversive emotional situations.

  8. Age-related changes in insulin sensitivity and β-cell function among European-American and African-American women.

    PubMed

    Chandler-Laney, Paula C; Phadke, Radhika P; Granger, Wesley M; Fernández, José R; Muñoz, Julian A; Man, Chiara Dalla; Cobelli, Claudio; Ovalle, Fernando; Gower, Barbara A

    2011-03-01

    Type 2 diabetes (T2D) is more prevalent among African-American (AA) than European-American (EA) women for reasons that are unknown. Ethnic differences in physiological processes related to insulin sensitivity (S(I)) and secretion, and age-related changes in these processes, may play a role. The purpose of this study was to identify ethnicity- and age-related differences in S(I) and β-cell responsivity among AA and EA females, and to determine whether these differences are independent of body composition and fat distribution. Healthy, normoglycemic females aged 7-12 years (n = 62), 18-32 years (n = 57), and 40-70 years (n = 49) were recruited for entry into this study. Following an overnight fast, S(I), intravenous glucose tolerance (Kg), acute C-peptide secretion (X0), and basal, first-phase, second-phase, and total β-cell responsivity to glucose (PhiB, Phi1, Phi2, and Phi(TOT), respectively) were measured by an intravenous glucose tolerance test. Total % body fat was assessed by dual-energy X-ray absorptiometry, and intra-abdominal adiposity (IAAT) by computed tomography. Main effects of age group and ethnicity were measured with analysis of covariance, adjusting for % fat, IAAT, and S(I) as indicated. AA had lower S(I), and higher Kg, X0, Phi1, and Phi(TOT) (P < 0.05), which remained after adjustment for % fat and IAAT. Greater X0, Phi1, and Phi(TOT) among AA were independent of S(I). Advancing age was associated with greater Phi2 among both EA and AA. To conclude, inherent ethnic differences in β-cell function exist independently of adiposity and S(I). Future research should examine whether ethnic differences in β-cell physiology contribute to disparities in T2D risk.

  9. Hepatitis C in African Americans.

    PubMed

    Saab, Sammy; Jackson, Christian; Nieto, Jose; Francois, Fritz

    2014-10-01

    The care of hepatitis C virus (HCV) in African Americans represents an opportunity to address a major health disparity in medicine. In all facets of HCV infection, African Americans are inexplicably affected, including in the prevalence of the virus, which is higher among them compared with most of the racial and ethnic groups. Ironically, although fibrosis rates may be slow, hepatocellular carcinoma and mortality rates appear to be higher among African Americans. Sustained viral response (SVR) rates have historically significantly trailed behind Caucasians. The reasons for this gap in SVR are related to both viral and host factors. Moreover, low enrollment rates in clinical trials hamper the study of the efficacy of anti-viral therapy. Nevertheless, the gap in SVR between African Americans and Caucasians may be narrowing with the use of direct-acting agents. Gastroenterologists, hepatologists, primary care physicians, and other health-care providers need to address modifiable risk factors that affect the natural history, as well as treatment outcomes, for HCV among African Americans. Efforts need to be made to improve awareness among health-care providers to address the differences in screening and referral patterns for African Americans.

  10. African Outreach Workshop 1974.

    ERIC Educational Resources Information Center

    Schmidt, Nancy J.

    This report discusses the 1974 African Outreach Workshop planned and coordinated by the African Studies Program at the University of Illinois at Urbana-Champaign. Its major aim was to assist teachers in developing curriculum units on African using materials available in their local community. A second aim was for the African Studies Program to…

  11. Africans in America.

    ERIC Educational Resources Information Center

    Hart, Ayanna; Spangler, Earl

    This book introduces African-American history and culture to children. The first Africans in America came from many different regions and cultures, but became united in this country by being black, African, and slaves. Once in America, Africans began a long struggle for freedom which still continues. Slavery, the Civil War, emancipation, and the…

  12. Corrugated cover plate for flat plate collector

    DOEpatents

    Hollands, K. G. Terry; Sibbitt, Bruce

    1978-01-01

    A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.

  13. Salinity-related variation in gene expression in wild populations of the black-chinned tilapia from various West African coastal marine, estuarine and freshwater habitats

    NASA Astrophysics Data System (ADS)

    Tine, Mbaye; McKenzie, David J.; Bonhomme, François; Durand, Jean-Dominique

    2011-01-01

    This study measured the relative expression of the genes coding for Na +, K +-ATPase 1α(NAKA), voltage-dependent anion channel (VDAC), cytochrome c oxidase-1 (COX), and NADH dehydrogenase (NDH), in gills of six wild populations of a West African tilapia species, acclimatised to a range of seasonal (rainy or dry) salinities in coastal, estuarine and freshwater sites. Previous laboratory experiments have demonstrated that these genes, involved in active ion transport, oxidative phosphorylation, and intra-cellular ATP transport, are relatively over-expressed in gill tissues of this species acclimated to high salinity. Positive correlations between relative expression and ambient salinity were found for all genes in the wild populations (Spearman rank correlation, p < 0.05), although for some genes these were only significant in either the rainy season or dry season. Most significantly, however, relative expression was positively correlated amongst the four genes, indicating that they are functionally interrelated in adaptation of Sarotherodon melanotheron to salinity variations in its natural environment. In the rainy season, when salinity was unstable and ranged between zero and 37 psu across the sites, overall mean expression of the genes was higher than in the dry season, which may have reflected more variable particularly sudden fluctuations in salinity and poorer overall water quality. In the dry season, when the salinity is more stable but ranged between zero and 100 psu across the sites, NAKA, NDH and VDAC expression revealed U-shaped relationships with lowest relative expression at salinities approaching seawater, between 25 and 45 psu. Although it is not simple to establish direct relationship between gene expression levels and energy requirement for osmoregulation, these results may indicate that costs of adaptation to salinity are lowest in seawater, the natural environment of this species. While S. melanotheron can colonise environments with extremely

  14. Growth Plate Fractures

    MedlinePlus

    .org Growth Plate Fractures Page ( 1 ) The bones of children and adults share many of the same risks for injury. But because they ... to a unique injury called a growth plate fracture. Growth plates are areas of cartilage located near ...

  15. The relational dynamics of hegemonic masculinity among South African men and women in the context of HIV.

    PubMed

    Stern, Erin; Buikema, Rosemarie

    2013-01-01

    In South Africa, the frequent positioning of men's sexual behaviours as a prime driver of the HIV epidemic has generated much interest in men's sexuality. However, the relational nature of dominant male norms that exacerbate the risk of HIV transmission is inadequately understood. This study used sexual biographies to explore how men and women negotiate gendered norms and how this affects their sexual and reproductive health (SRH). A total of 50 sexual-history interviews and 10 focus group discussions were conducted with men, and 25 sexual-history interviews with women, with participants sampled from three age categories (ages 18-24, 25-55 and 55+years), a range of cultural and racial backgrounds and urban and rural sites across five provinces in South Africa. The narratives illustrate that men and women's SRH is largely dependent on the type and quality of their relationships. Men's sexuality was regularly depicted as being detached from intimacy and uncontrollable, which was premised as being opposite from and/or superior to women's sexuality and could justify men's high-risk sexual behaviours. Yet many participants also supported gender equitable relationships and endorsed accountable and healthy SRH behaviours. The narratives reveal that HIV-risky dominant male norms should be addressed relationally for the sake of better SRH outcomes.

  16. Ethnic group-related differences in CpG hypermethylation of the GSTP1 gene promoter among African-American, Caucasian and Asian patients with prostate cancer.

    PubMed

    Enokida, Hideki; Shiina, Hiroaki; Urakami, Shinji; Igawa, Mikio; Ogishima, Tatsuya; Pookot, Deepa; Li, Long-Cheng; Tabatabai, Z Laura; Kawahara, Motoshi; Nakagawa, Masayuki; Kane, Christopher J; Carroll, Peter R; Dahiya, Rajvir

    2005-08-20

    The incidence and mortality of prostate cancer (PC) is approximately 2-fold higher among African-Americans as compared to Caucasians and very low in Asian. We hypothesize that inactivation of GSTP1 genes through CpG methylation plays a role in the pathogenesis of PC, and its ability to serve as a diagnostic marker that differs among ethnic groups. GSTP1 promoter hypermethylation and its correlation with clinico-pathological findings were evaluated in 291 PC (Asian = 170; African-American = 44; Caucasian = 77) and 172 benign prostate hypertrophy samples (BPH) (Asian = 96; African-American = 38; Caucasian = 38) using methylation-specific PCR. In PC cells, 5-aza-dC treatment increased expression of GSTP1 mRNA transcripts. The methylation of all CpG sites was found in 191 of 291 PC (65.6%), but only in 34 of 139 BPH (24.5%). The GSTP1 hypermethylation was significantly higher in PC as compared to BPH in each ethnic group (p < 0.0001). Logistic regression analysis (PC vs. BPH) showed that African-Americans had a higher hazard ratio (HR) (13.361) compared to Caucasians (3.829) and Asian (8.603). Chi-square analysis showed correlation of GSTP1 hypermethylation with pathological findings (pT categories and higher Gleason sum) in Asian PC (p < 0.0001) but not in African-Americans and Caucasian PC. Our results suggest that GSTP1 hypermethylation is a sensitive biomarker in African-Americans as compared to that in Caucasians or Asian, and that it strongly influences tumor progression in Asian PC. Ours is the first study investigating GSTP1 methylation differences in PC among African-American, Caucasian and Asian.

  17. Shedding dynamics of Morogoro virus, an African arenavirus closely related to Lassa virus, in its natural reservoir host Mastomys natalensis.

    PubMed

    Borremans, Benny; Vossen, Raphaël; Becker-Ziaja, Beate; Gryseels, Sophie; Hughes, Nelika; Van Gestel, Mats; Van Houtte, Natalie; Günther, Stephan; Leirs, Herwig

    2015-05-29

    Arenaviruses can cause mild to severe hemorrhagic fevers. Humans mainly get infected through contact with infected rodents or their excretions, yet little is known about transmission dynamics within rodent populations. Morogoro virus (MORV) is an Old World arenavirus closely related to Lassa virus with which it shares the same host species Mastomys natalensis. We injected MORV in its host, and sampled blood and excretions at frequent intervals. Infection in adults was acute; viral RNA disappeared from blood after 18 days post infection (dpi) and from excretions after 39 dpi. Antibodies were present from 7 dpi and never disappeared. Neonatally infected animals acquired a chronic infection with RNA and antibodies in blood for at least 3 months. The quantified excretion and antibody patterns can be used to inform mathematical transmission models, and are essential for understanding and controlling transmission in the natural rodent host populations.

  18. Babies who die from labour-related intrapartum hypoxia: a confidential enquiry in South African public hospitals.

    PubMed

    Buchmann, E J; Pattinson, R C

    2006-01-01

    Seventeen hospitals, from a range of health-care environments, participated in confidential enquiries of perinatal deaths resulting from labour-related intrapartum hypoxia. There were 102 deaths, including 22 stillbirths and 80 neonatal deaths. The mean birthweight was 3021 g. The active phase of the first stage of labour was prolonged beyond 12 h in six cases, and oxytocin was used for induction or augmentation in 10 women. Fetal heart decelerations were detected in 39 (49%) of the babies that went on to die in the neonatal period, and meconium passage was evident in 50 (63%). There were six breech presentations, and seven cases of cord prolapse. The majority of these deaths occurred in low-risk women with apparently uncomplicated labour. There appears to be a failure to detect or respond to evidence of fetal distress. Intrapartum care for all women in labour requires close attention to detail in monitoring fetal health.

  19. Shedding dynamics of Morogoro virus, an African arenavirus closely related to Lassa virus, in its natural reservoir host Mastomys natalensis

    PubMed Central

    Borremans, Benny; Vossen, Raphaël; Becker-Ziaja, Beate; Gryseels, Sophie; Hughes, Nelika; Van Gestel, Mats; Van Houtte, Natalie; Günther, Stephan; Leirs, Herwig

    2015-01-01

    Arenaviruses can cause mild to severe hemorrhagic fevers. Humans mainly get infected through contact with infected rodents or their excretions, yet little is known about transmission dynamics within rodent populations. Morogoro virus (MORV) is an Old World arenavirus closely related to Lassa virus with which it shares the same host species Mastomys natalensis. We injected MORV in its host, and sampled blood and excretions at frequent intervals. Infection in adults was acute; viral RNA disappeared from blood after 18 days post infection (dpi) and from excretions after 39 dpi. Antibodies were present from 7 dpi and never disappeared. Neonatally infected animals acquired a chronic infection with RNA and antibodies in blood for at least 3 months. The quantified excretion and antibody patterns can be used to inform mathematical transmission models, and are essential for understanding and controlling transmission in the natural rodent host populations. PMID:26022445

  20. Mind-Body Interventions to Reduce Risk for Health Disparities Related to Stress and Strength Among African American Women: The Potential of Mindfulness-Based Stress Reduction, Loving-Kindness, and the NTU Therapeutic Framework.

    PubMed

    Woods-Giscombé, Cheryl L; Black, Angela R

    2010-12-14

    In the current article, the authors examine the potential role of mind-body interventions for preventing or reducing health disparities in a specific group-African American women. The authors first discuss how health disparities affect this group, including empirical evidence regarding the influence of biopsychosocial processes (e.g., psychological stress and social context) on disparate health outcomes. They also detail how African American women's unique stress experiences as a result of distinct sociohistorical and cultural experiences related to race and gender potentially widen exposure to stressors and influence stress responses and coping behaviors. Using two independent, but related, frameworks (Superwoman Schema [SWS] and the Strong Black Woman Script [SBW-S]), they discuss how, for African American women, stress is affected by "strength" (vis-à-vis resilience, fortitude, and self-sufficiency) and the emergent health-compromising behaviors related to strength (e.g., emotional suppression, extraordinary caregiving, and self-care postponement). The authors then describe the potential utility of three mind-body interventions-mindfulness-based stress reduction (MBSR), loving-kindness meditation (LKM), and NTU psychotherapy-for specifically targeting the stress-, strength-, and contextually related factors that are thought to influence disparate outcomes for African American women. Self-awareness, self-care, inter- and intrapersonal restorative healing and a redefinition of inner strength may manifest through developing a mindfulness practice to decrease stress-related responses; using LKM to cultivate compassion and forgiveness for self and others; and the balance of independence and interdependence as a grounding NTU principle for redefining strength. The authors conclude with a discussion of potential benefits for integrating key aspects of the interventions with recommendations for future research.

  1. Mind-Body Interventions to Reduce Risk for Health Disparities Related to Stress and Strength Among African American Women: The Potential of Mindfulness-Based Stress Reduction, Loving-Kindness, and the NTU Therapeutic Framework

    PubMed Central

    Woods-Giscombé, Cheryl L.; Black, Angela R.

    2011-01-01

    In the current article, the authors examine the potential role of mind-body interventions for preventing or reducing health disparities in a specific group—African American women. The authors first discuss how health disparities affect this group, including empirical evidence regarding the influence of biopsychosocial processes (e.g., psychological stress and social context) on disparate health outcomes. They also detail how African American women's unique stress experiences as a result of distinct sociohistorical and cultural experiences related to race and gender potentially widen exposure to stressors and influence stress responses and coping behaviors. Using two independent, but related, frameworks (Superwoman Schema [SWS] and the Strong Black Woman Script [SBW-S]), they discuss how, for African American women, stress is affected by “strength” (vis-à-vis resilience, fortitude, and self-sufficiency) and the emergent health-compromising behaviors related to strength (e.g., emotional suppression, extraordinary caregiving, and self-care postponement). The authors then describe the potential utility of three mind-body interventions—mindfulness-based stress reduction (MBSR), loving-kindness meditation (LKM), and NTU psychotherapy—for specifically targeting the stress-, strength-, and contextually related factors that are thought to influence disparate outcomes for African American women. Self-awareness, self-care, inter- and intrapersonal restorative healing and a redefinition of inner strength may manifest through developing a mindfulness practice to decrease stress-related responses; using LKM to cultivate compassion and forgiveness for self and others; and the balance of independence and interdependence as a grounding NTU principle for redefining strength. The authors conclude with a discussion of potential benefits for integrating key aspects of the interventions with recommendations for future research. PMID:21479157

  2. Diversity among African Pygmies

    PubMed Central

    Ramírez Rozzi, Fernando V.; Sardi, Marina L.

    2010-01-01

    Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies. PMID:21049030

  3. Miocene to Pliocene changes in South African hydrology and vegetation in relation to the expansion of C4 plants

    NASA Astrophysics Data System (ADS)

    Dupont, Lydie M.; Rommerskirchen, Florian; Mollenhauer, Gesine; Schefuß, Enno

    2013-08-01

    The Miocene expansion of C4 plants (mainly tropical grasses) between 8 and 4 million years (Ma) remains an enigma since regional differences in the timing of the expansion rules out decreased CO2 (pCO2) as a dominant forcing [e.g. Tipple and Pagani, 2007. The early origins of terrestrial C4 photosynthesis. Annu. Rev. Earth Planet. Sci. 35, 435-461]. Other environmental factors, such as low-latitude aridity and seasonality have been proposed to explain the low tree versus grass ratio found in savannahs and tropical grasslands of the world, but conclusive evidence is missing. Here we use pollen and stable carbon (δ13C) and hydrogen (δD) isotope ratios of terrestrial plant wax from a South Atlantic sediment core (ODP Site 1085) to reconstruct Miocene to Pliocene changes of vegetation and rainfall regime of western southern Africa. Our results reveal changes in the relative amount of precipitation and indicate a shift of the main moisture source from the Atlantic to the Indian Ocean during the onset of a major aridification 8 Ma ago. We emphasize the importance of declining precipitation during the expansion of C4 and CAM (mainly succulent) vegetation in South Africa. We suggest that the C4 plant expansion resulted from an increased equator-pole temperature gradient caused by the initiation of strong Atlantic Meridional Overturning Circulation following the shoaling of the Central American Seaway during the Late Miocene.

  4. African (Black) Psychology: Issues and Synthesis.

    ERIC Educational Resources Information Center

    Baldwin, Joseph A.

    1986-01-01

    Reviews the recent attempts of Black psychologists and social scientists to formulate a conceptual-operational framework for the study of psychological phenomena as they bear on the cultural-survival conditions of Black-African people. Outlines issues and problems in the attempt to define African (Black) psychology and discusses its relation to…

  5. Genetics Home Reference: African iron overload

    MedlinePlus

    ... of a genetic condition? Genetic and Rare Diseases Information Center Frequency African iron overload is common in rural areas of central and ... more about the gene associated with African iron overload SLC40A1 Related Information What is a gene? What is a gene ...

  6. From lizard body form to serpentiform morphology: The atlas-axis complex in African cordyliformes and their relatives.

    PubMed

    Čerňanský, Andrej

    2016-04-01

    The comparative vertebral morphology of the atlas-axis complex in cordyliforms, xantusiid and several skinks is studied here. These lizards are particularly interesting because of their different ecological adaptations and anti-predation strategies, where conformation ranges from the lizard-like body to a snake-like body. This transition to serpentiform morphology shows several evolutionary patterns in the atlas-axis complex: 1) the zygapophyseal articulations are lost in the early stage of the transition. In contrast to mammals, the atlas is more or less locked to the axis in lepidosaurs, but the absence of zygapophyseal articulation releases this locking for rotation. However despite its serpentiform morphology, Chamaesaura is different, in possessing this articulation; 2) the first intercentrum of Chamaesaura and Tetradactylus africanus (serpentiform grass-swimmers) is fully curved anteriorly, underlying the occipital condyle. While this limits ventral skull rotation beyond a certain angle, it locks the skull, which is a crucial adaptation for a sit-and-wait position in grassland habitats that needs to keep the head stabilized; and 3) in Acontias, most of the atlas articular surface with the occipital condyle is formed by the lateral aspect of the articulation area relative to the area located in the dorsal region of the slightly reduced intercentrum. A similar state occurs in amphisbaenians, most likely reflecting a fossorial lifestyle of the limbless lizards. Although Chamaesaura and Tetradactylus live sympatrically in grasslands, Chamaesaura differs in several ways in atlas-axis complex: for example, aforementioned presence of the atlas-axis zygapophyseal articulation, and long posterodorsal processes. Its occipital condyle protrudes further posteriorly, placing the atlas-axis complex further from the endocranium than in Tetradactylus. Hence, adaptation in the same niche, even among sister clades, can lead to different atlas-axis morphology due to different

  7. Relative toxicity of spent lubricant oil and detergent against benthic macro-invertebrates of a west African estuarine lagoon.

    PubMed

    Chukwu, L O; Odunzeh, C C

    2006-07-01

    The relative acute toxicity of spent lubricant oil and detergent was evaluated against hermit crab, Clibanarius africanus (Aurivillus) and periwinkle, Tympanotonus fuscatus (L) from the Lagos lagoon in laboratory bioassays. Based on the derived toxicity indices, the detergent (96 hr LC50 = 5.77ml/l) was found to be 1.73 times more toxic than spent engine oil (96 hr LC50 = 10.01 ml/l) when acting singly against C africanus and 18.73 times (96 hr LC50-48.67 ml/l) more toxic (96 hr LC50 = 911.57 ml/l) when acting singly against T. fuscatus. On the basis of the computed susceptibility factors, C. africanus was found to be about eight times and ninety-one times more susceptible to the toxic effect of detergent and spent lubricant oil respectively. The randomized analysis of variance (ANOVA) showed that there was significant difference (Fcal 58.83 Ftab 3.87; DF 13; p > 0.05) between all treatments of spent lubricant oil and detergent during the 96 hr exposure period of test animals. At 5% level of significance the Student Neuman-Keuls (SNK) test further revealed significant differences in the mean mortality response of test animals exposed to toxicants at all concentrations and untreated control. The results obtained in this study suggest that the estuarine benthic macroinvertebrates, which play key roles in the environment, may serve as useful in-situ sentinels for biomonitoring studies of petroleum pollutants in fragile aquatic ecosystems such as the Lagos lagoon.

  8. Proxy Assessment of Health-Related Quality of Life in African American and White Respondents With Prostate Cancer

    PubMed Central

    Pickard, A. Simon; Lin, Hsiang-Wen; Knight, Sara J.; Sharifi, Roohollah; Wu, Zhigang; Hung, Shih-Ying; Witt, Whitney P.; Chang, Chih-Hung; Bennett, Charles L.

    2011-01-01

    Objectives An emerging issue in the proxy literature is whether specifying different proxy viewpoints contributes to different health-related quality of life (HRQL) assessments, and if so, how might each perspective be informative in medical decision making. The aims of this study were to determine if informal caregiver assessments of patients with prostate cancer differed when prompted from both the patient perspective (proxy-patient) and their own viewpoint (proxy-proxy), and to identify factors associated with differences in proxy perspectives (ie, the intraproxy gap). Research Design and Methods Using a cross-sectional design, prostate cancer patients and their informal caregivers were recruited from urology clinics in the Jesse Brown Veterans Affairs Healthcare System in Chicago. Dyads assessed HRQL using the EQ-5D visual analog scale (VAS) and EORTC QLQ-C30. Results Of 87 dyads, most caregivers were female (83%) and were spouses/partners (58%). Mean difference scores between proxy-patient and proxy-proxy perspectives were statistically significant for QLQ-C30 physical and emotional functioning, and VAS (all P < 0.05), with the proxy-patient perspective closer to patient self-report. Emotional functioning had the largest difference, mean 6.0 (SD 12.8), an effect size = 0.47. Factors weakly correlated with the intraproxy gap included relationship (spouse) and proxy gender for role functioning, and health literacy (limited/functional) for physical functioning (all P < 0.05, 0.20 < r < 0.35). Conclusions Meaningful differences between proxy-patient and proxy-proxy perspectives on mental health were consistent with a conceptual framework for understanding proxy perspectives. Prompting different proxy viewpoints on patient health could help clinicians identify patients who may benefit from clinical intervention. PMID:19169118

  9. Diversity and functionality of Bacillus and related genera isolated from spontaneously fermented soybeans (Indian Kinema) and locust beans (African Soumbala).

    PubMed

    Sarkar, P K; Hasenack, B; Nout, M J R

    2002-08-25

    A total of 126 isolates of Bacillus and related genera from indigenous, spontaneously fermented soybeans (Kinema) and locust beans (Soumbala) were characterized with the purpose of defining interspecific, as well as intraspecific relationships among the components of their microflora. B. subtilis was the dominant species, and species diversity was more pronounced in Soumbala than in Kinema. While from Kinema, six species were isolated (B. subtilis, B. licheniformis, B. cereus, B. circulans, B. thuringiensis and B. sphaericus), in Soumbala, the species found were B. subtilis, B. thuringiensis, B. licheniformis, B. cereu, B. badius, Paenibacillus alvei, B. firmus, P. larvae, Brevibacillus laterosporus, B. megaterium, B. mycoides and B. sphaericus. Genomic diversity in the isolates of B. subtilis was investigated by random amplified polymorphic DNA (RAPD) analysis using the polymerase chain reaction (PCR). The RAPD-PCR fingerprint analysis showed a high level of diversity. With more than 90% similarity, all 52 RAPD subdivisions were source and continent-wise homogeneous. Profiles of carbon source fermentation also showed a wide but corresponding phenotypic diversity, largely corresponding with RAPD subdivisions. The various strains were tested for several criteria for functionality in soybean fermentation, viz. protein degradation, pH increase, and development of desirable stickiness caused by viscous exopolymers. Profiles of functionality, based upon estimations of pH, free amino nitrogen and stickiness were associated with genotypic and phenotypic profiles. Notwithstanding the heterogenous fermentation results for some genotypic profiles, a ranking of RAPD groups is possible and can be useful in the further selection and study of B. subtilis strains.

  10. Teacher- or Learner-Centred? Science Teacher Beliefs Related to Topic Specific Pedagogical Content Knowledge: A South African Case Study

    NASA Astrophysics Data System (ADS)

    Mavhunga, Elizabeth; Rollnick, Marissa

    2016-12-01

    In science education, learner-centred classroom practices are widely accepted as desirable and are associated with responsive and reformed kinds of teacher beliefs. They are further associated with high-quality Pedagogical Content Knowledge (PCK). Topic-Specific Pedagogical Content Knowledge (TSPCK), a version of PCK defined at topic level, is known to enable the transformation of topic content into a form accessible to learners. However, little is known about teacher science beliefs in relation to TSPCK and therefore the nature of likely associated classroom practices. In this study, we investigated the relationship between TSPCK and underlying science teacher beliefs following an intervention targeting the improvement of TSPCK in the topic chemical equilibrium. Sixteen final year pre-service chemistry teachers were exposed to an intervention that explicitly focussed on knowledge for transforming the content of chemical equilibrium using the five knowledge components of TSPCK. A specially designed TSPCK instrument in chemical equilibrium and the Teacher Belief Instrument (TBI) were used to capture written responses in pre- and post-tests. Additional qualitative data was collected from audio-recorded discussions and written responses from an open-ended question asked before and after the intervention. Two key findings emerged from the study. Firstly, the development of TSPCK was linked to shifts in underlying science teacher beliefs in the direction of learner-centred teaching for the majority of pre-service teachers. Secondly, this shift was not evident for all, as for some there was development of TSPCK without a shift from teacher-centred beliefs about science teaching.

  11. Productivity paradox in the NW African upwelling area during the last glaciation related to changes in nutricline depth and Saharan humid episodes

    NASA Astrophysics Data System (ADS)

    Meggers, H.; Prange, M.; Kuhlmann, H.; Freudenthal, T.; Schulz, M.; Hensen, C.; Plewa, K.

    2009-04-01

    The Sahara is the largest desert of the world. However, during the early Holocene the Saharan realm was nearly completely vegetated within the "African humid period". This period has been attributed to a strengthening and northward extension of the summer monsoon. Our reconstructions of marine productivity and terrigenous input from a sediment core off NW Africa provide a detailed record of subtropical climate from 45,000 to 3,000 years BP. We show that abrupt climatic changes modulated the precessionally forced paleoproductivity-signal off NW Africa. Cold periods with increased upwelling intensity show low productivity due to a deepening of the nutricline depth during the winter bloom. Although the glacial in NW Africa is believed to be a dry and cold period, our data indicate wet phases during the insolation maximum in marine isotopic stage 3. These glacial "Saharan humid episodes" would have offered ecological conditions almost resembling those of the early Holocene. Core GeoB 5546 was retrieved at 27°32`N, 13°44`W at 1070 m water-depth off Cape Yubi. The average sedimentation rate of 20 cm /1000 years is caused by the combined influence of high regional surface ocean productivity and high supply of terrigenous material, partly windblown African mineral dust and partly wadi/river transported material. Along with fourteen 14C-datings, the δ18O-values of the planktonic foraminifera G. bulloides were used for stratigraphy. At present, productivity in the Eastern Boundary Current region of the NE Atlantic is seasonal and closely linked to two major processes, that is, coastal upwelling in summer and deep mixing with an associated bloom in winter. High TOC contents of up to 1.5 % occur during interstadials, whereas lower values (0.6-0.9 %) prevail during stadials. If wind-driven coastal upwelling was the major process that controls the paleoproductivity in the Eastern Boundary Current, this finding would contradict modelling results which indicate strengthened NE

  12. Martian plate tectonics

    NASA Astrophysics Data System (ADS)

    Sleep, N. H.

    1994-03-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses

  13. Achievement and Underachievement: The Experiences of African Caribbeans

    ERIC Educational Resources Information Center

    Rhamie, Jasmine

    2012-01-01

    The disproportionate representation of African Caribbeans in all the negative educational statistics has been well documented. Despite this, there are African Caribbeans who achieve academically but relatively few studies have explored this area. This study aimed to investigate the factors that contribute to African Caribbean academic success,…

  14. African American Males in Counseling: Who's Pulling the Trigger Now?

    ERIC Educational Resources Information Center

    Bethea-Whitfield, Patricia

    African American males face numerous challenges to their physical and psychological well-being. This project is a survey of the literature and trends relative to African American males from 1987 to the present. In reviewing the fifteen years since Parham and McDavis published their now famous article on African American men as an endangered…

  15. The transition from linear to diffuse plate boundary in the Azores-Gibraltar region: results from a thin-sheet model

    NASA Astrophysics Data System (ADS)

    Jiménez-Munt, Ivone; Fernàndez, Manel; Torne, Montse; Bird, Peter

    2001-10-01

    We use the thin-sheet plane-stress approach to study the present-day dynamic behavior of the plate boundary between Eurasia and Africa along the Azores-Gibraltar region. This plate boundary, which extends from the Azores triple junction to the Gibraltar strait, shows a tectonic regime that changes from transtension in the west to transpression in the east, with a strike-slip motion in its central segment. Seismological data reveal that the western and central segments are currently marked by a linear series of earthquakes indicating that the plate boundary is located in a narrow zone. In contrast, the eastern segment is not so well defined and deformation spreads over a much broader area. To apply the thin-sheet approach, we combined heat flow, elevation and crustal thickness data to calculate the steady-state geotherm and the total strength of the lithosphere. Several models with different fault friction coefficients and geometries at the eastern segment of the plate boundary were tested. Results are compared with the maximum compressive stress directions from the World Stress Map, and the calculated seismic strain rates and slip vectors from earthquake data. The best fitting models are consistent with the rotation pole of Argus et al. [D.F. Argus et al., J. Geophys. Res. 94 (1989) 5585-5602], and show that the rheological behavior of the plate boundary must necessarily change from the western and central segments to the eastern segment. The diffuse character of the plate boundary east of the Gorringe Bank is dominated by the transition from oceanic to continental lithosphere, the weakness of the Alboran domain, and the convergence between the African and the Eurasian plates. The displacement of the Alboran domain relative to the African plate may play a major role in stress propagation through the Iberian Peninsula and its Atlantic margin.

  16. The Relation of Maternal Birth Weight to African-American and Non-Latina White Twin Pregnancy Outcomes: A Population-Based Study.

    PubMed

    McAndrew, Sarah; Chihara, Izumi; Rankin, Kristin M; Collins, James W

    2016-07-28

    Objectives The authors investigated the association between maternal birth weight and adverse birth outcome as measured by rates of low birth weight (<2500 g, LBW), preterm birth (<37 weeks, PTB), and small for gestational age (weight <10th percentile for gestational age, SGA) among African American and White twin pregnancies. Methods Stratified and multivariable regression analyses were performed on the Illinois transgenerational dataset of non-Latina African American and non-Latina White twin pairs (born 1989-1991) and their mothers (born 1956-1976). Results Former LBW (n = 104) and non-LBW (n = 742) African American mothers had LBW rates in both twins of 76 and 56 %, respectively; RR (95 % CI) = 1.4 (1.2-1.6). Former LBW (n = 105) and non-LBW (n = 2136) White mothers had LBW rates in both twins of 41 and 34 %, respectively; RR = 1.2 (0.9-1.5). In multivariable regression models, the adjusted (controlling for maternal age, education, marital status, parity, prenatal care usage, and cigarette smoking) RR of LBW in both twins among former LBW (compared to non-LBW) African American and White mothers equaled 1.4 (1.2-1.6) and 1.2 (0.9-1.5), respectively. Maternal LBW was associated with a modestly increased risk of PTB but not SGA among African American twin pregnancies: adjusted RR = 1.3 (1.1-1.4) and 1.1 (0.8-1.5), respectively. Conclusions In African American twin pregnancies, maternal LBW is a risk factor for LBW in both twins. Further research is needed to determine whether a similar generational association occurs among non-Latina White twin pregnancies.

  17. A web-based survey of horse owners' perceptions and network analysis of horse movements relating to African horse sickness distribution in Namibia and South Africa.

    PubMed

    Liebenberg, Danica; Piketh, Stuart; van Hamburg, Huib

    2016-06-01

    Africa horse sickness (AHS) is the most lethal infectious non-contagious horse disease and has accordingly been declared notifiable by the World Organisation for Animal Health. AHS is endemic to sub-Saharan Africa and causes considerable losses to the equestrian industry. The effect of diseases in livestock on socio-economic factors is well researched, but the effect of anthropogenic factors on the distribution of a disease is poorly understood. The purpose of the study was to assess Namibian and South African horse owners' perceptions and the effect of horse movement on AHS distribution. A cross-sectional study was conducted to collect information from horse owners in Namibia and South Africa. To that end 'Fluid survey' was used for survey development. The survey was launched on Facebook and the link shared to horse related focus groups in Namibia and South Africa. A total of 508 responses were collected during the survey period. Of the 417 completed questionnaires received, 22% were from Namibia and 78% from South Africa. The participants comprised of 71% social and 29% professional riders. The most popular precautionary measures used, in addition to vaccination, were chemical repellents (64%) and stabling of horses during dusk and dawn (59%). A network analysis was performed in Gephi 0.8.2.B to illustrate the movement of horses between countries and districts/provinces. Network analysis results indicate that areas with the highest movement of horses corresponded to the areas with a high occurrence of AHS. Although 93% of the participants were aware that AHS is a notifiable and controlled disease, the process and efficiency of reporting is mostly unknown. With this snapshot of horse owners' perceptions and the effect of horse movement on the distribution of AHS, it is clear that a more holistic approach is needed. To that end, all environmental and social factors must be taken into account in effective management strategies.

  18. [Age-related changes in bone mineral density, mean width and area of the lumbar vertebrae in male African green monkeys (Cercopithecus aethiops)].

    PubMed

    Hiyaoka, A; Yoshida, T; Cho, F; Yoshikawa, Y

    1994-04-01

    We were able to measure bone mineral density (BMD), mean bone width and the area of the lumbar vertebrae in male African green monkeys with a dual-energy X-ray absorptiometry (DPX-alpha, Lunar, USA). For analysis of spinal bone mass, mean width and area of the bone, we scanned lumbar vertebrae L3-L5 using a pediatric analysis program. We used restraining bed made of formed polystyrol to support the animal in a supine position. The precision of the measuring technique was calculated by averaging the coefficients of variance of the 5 scans obtained in 5 animals aged from 5 to 7 years. The precision values for BMD, bone width and area were 1.9%, 0.9% and 2.6%, respectively. Furthermore, age-related changes in bone measurements were demonstrated using laboratory-bred males (n = 45) and, additionally, wild-originated males (n = 7, estimated ages over 15 years old). The values of B M D, bone width and area at 6 months old were about 0.3 g/cm2, 1.2cm and 4.5 cm2 respectively. These values increased with aging to about 0.7 g/cm2, 1.5 cm and 11cm2 at 5 years old, respectively, and were judged to reach plateau. However, animals over 10 years old and wild-originated animals which had been kept over 10 years in our breeding colony showed rather smaller BMD and area values than the animals aged 5 to 10 years. The animals aged between 5 and 10 years seemed to have retained a peak bone mass in this primate species.

  19. Deciphering Detailed Plate Kinematics of the Indian Ocean: A Combined Indian-Australian-French Initiative

    NASA Astrophysics Data System (ADS)

    Vadakkeyakath, Y.; Müller, R.; Dyment, J.; Bhattacharya, G.; Lister, G. S.; Kattoju, K. R.; Whittaker, J.; Shuhail, M.; Gibbons, A.; Jacob, J.; White, L. T.; Bissessur, P. D.; Kiranmai, S.

    2012-12-01

    The Indian Ocean formed as a result of the fragmentation and dispersal of East Gondwanaland since the Jurassic. The deep ocean basins in the Indian Ocean contain the imprints of this plate tectonic history, which is related with several major events such as the Kerguelen, Marion and Reunion hotspot inception and the Indo-Eurasian collision. A broad model for evolution of the Indian Ocean was proposed in the early 1980s. Subsequently, French scientists collected a large amount of magnetic data from the western and southern parts of the Indian Ocean while Indian and Australian scientists collected considerable volumes of magnetic data from the regions of Indian Ocean around their mainlands. Using these data, the Indian, French and Australian researchers independently carried out investigations over different parts of the Indian Ocean and provided improved models of plate kinematics at different sectoral plate boundaries. Under two Indo-French collaborative projects, detailed magnetic investigations were carried out in the Northwestern and Central Indian Ocean by combining the available magnetic data from conjugate regions. Those projects were complemented by additional area-specific studies in the Mascarene, Wharton, Laxmi and Gop basins, which are characterized by extinct spreading regimes. These Indo-French projects provided high resolution and improved plate tectonic models for the evolution of the conjugate Arabian and Eastern Somali basins that constrain the relative motion between the Indian-African (now Indian-Somalian) plate boundaries, and the conjugate Central Indian, Crozet and Madagascar basins that mainly constrain the relative motions of Indian-African (now Capricorn-Somalian) and Indian-Antarctic (now Capricorn-Antarctic) plate boundaries. During the same period, Australian scientists carried out investigations in the southeastern part of the Indian Ocean and provided an improved understanding of the plate tectonic evolution of the Indian

  20. Sputtering and ion plating

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.

  1. Summary of the stratigraphy and structural elements related to plate convergence of the Quetta-Muslim Bagh-Sibi region, Balochistan, west-central Pakistan

    USGS Publications Warehouse

    Maldonado, Florian; Mengal, Jan M.; Khan, Shahid H.; Warwick, Peter D.

    2011-01-01

    The four major faults that bound the structural terrane are the Frontal (F), Ghazaband-Zhob (GZ), Gwal-Bagh (GB), and Chaman (C) faults. Four major periods of deformation are recognized: (1) emplacement of ophiolitic rocks onto the continental margin of the India plate; (2) convergence of the India-Eurasia plates; (3) deposition of Tertiary-Quaternary molasse units followed by major folding and thrusting, and formation of strike-slip faults; and (4) deposition of Pleistocene molasse units with subsequent folding, thrusting, and strike-slip motion that continues to the present.

  2. Geomorphometric reconstruction of post-eruptive surfaces of the Virunga Volcanic Province (East African Rift), constraint of erosion ratio and relative chronology

    NASA Astrophysics Data System (ADS)

    Lahitte, Pierre; Poppe, Sam; Kervyn, Matthieu

    2016-04-01

    Quaternary volcanic landforms result from a complex evolution, involving volcanic constructional events and destructive ones by collapses and long-term erosion. Quantification, by morphometric approaches, of the evolution through time of the volcano shape allows the estimation of relative ages between volcanoes sharing the same climate and eruptive conditions. We apply such method to six volcanoes of the Virunga Volcanic Province in the western branch of the East African Rift Valley that still has rare geochronological constraints. As they have comparable sizes, volcanic history and erupted products, these edifices may have undergone comparable conditions of erosion which justify the deduction of relative chronology from their erosion pattern. Our GIS-based geomorphometric approach, the SHAPEVOLC algorithm, quantifies erupted or dismantled volumes by numerically modeling topographies resulting from the eruptive construction of each volcano. Constraining points are selected by analyses of morphometric properties of each cell of the current DEM, as the loci where the altitude is still representative of the un-eroded volcanic surfaces. A primary elevation surface is firstly adjusted to these constraining points by modeling a first-order pseudo-radial surface defined by: 1. the curve best fitting the concave-upwards volcano profile; 2. the location and elevation of the volcano summit; and 3. the possible eccentricity and azimuth parameters that allow to stretch and contract contours to adjust the shape of the model to the elliptically-shaped surface of the volcano. A second-order surface is next computed by local adjustment of the first-order surface to the constraining points to obtain the definitive primary elevation surface of the considered volcanic construct. Amount of erosion is obtained by summing the difference in elevation between reconstructed surfaces and current ones that allows to establish relative ages of volcanoes. For the 6 studied Virunga volcanoes

  3. The African Pediatric Fellowship Program: Training in Africa for Africans.

    PubMed

    Wilmshurst, Jo M; Morrow, Brenda; du Preez, Avril; Githanga, David; Kennedy, Neil; Zar, Heather J

    2016-01-01

    Africa has a significant burden of childhood disease, with relatively few skilled health care professionals. The African Paediatric Fellowship Programme was developed by the Department of Pediatrics and Child Health at the University of Cape Town to provide relevant training for African child health professionals, by Africans, within Africa. Trainees identified by partner academic institutions spend 6 months to 2 years training in the Department of Pediatrics and allied disciplines. They then return to their home institution to build practice, training, research, and advocacy. From 2008 to 2015, 73 physicians have completed or are completing training in general pediatrics or a pediatric subspecialty. At 1 year posttraining, 98% to 100% are practicing back in their home institution. The impact of the returning fellows is evident from their practice interventions, research collaborations, and positions as stakeholders who can change health care policies. Thirty-three centers in 13 African countries are partners with the program, and the program template is now followed by other partner sites in Africa. Increasing and retaining the skills pool of African child health specialists is building a network of motivated, highly skilled clinicians who are equipped to advance child health in Africa.

  4. Plate motion and deformation

    SciTech Connect

    Minster, B.; Prescott, W.; Royden, L.

    1991-02-01

    Our goal is to understand the motions of the plates, the deformation along their boundaries and within their interiors, and the processes that control these tectonic phenomena. In the broadest terms, we must strive to understand the relationships of regional and local deformation to flow in the upper mantle and the rheological, thermal and density structure of the lithosphere. The essential data sets which we require to reach our goal consist of maps of current strain rates at the earth's surface and the distribution of integrated deformation through time as recorded in the geologic record. Our success will depend on the effective synthesis of crustal kinematics with a variety of other geological and geophysical data, within a quantitative theoretical framework describing processes in the earth's interior. Only in this way can we relate the snapshot of current motions and earth structure provided by geodetic and geophysical data with long-term processes operating on the time scales relevant to most geological processes. The wide-spread use of space-based techniques, coupled with traditional geological and geophysical data, promises a revolution in our understanding of the kinematics and dynamics of plate motions over a broad range of spatial and temporal scales and in a variety of geologic settings. The space-based techniques that best address problems in plate motion and deformation are precise space-geodetic positioning -- on land and on the seafloor -- and satellite acquisition of detailed altimetric and remote sensing data in oceanic and continental areas. The overall science objectives for the NASA Solid Earth Science plan for the 1990's, are to Understand the motion and deformation of the lithosphere within and across plate boundaries'', and to understand the dynamics of the mantle, the structure and evolution of the lithosphere, and the landforms that result from local and regional deformation. 57 refs., 7 figs., 2 tabs.

  5. How is Silurian-Early Devonian faulting in the North America continental interior related to orogenic processes at plate boundaries? A working hypothesis from the Canadian North

    NASA Astrophysics Data System (ADS)

    Pinet, Nicolas

    2015-04-01

    The Paleozoic Appalachian/Franklinian orogen that rims the North America continent on its eastern and northern sides is comparable in size with Tethyan orogenic belts. However, the far-field effects in the continental interior of the multiple Ordovician to Carboniferous deformation phases that built the orogen were relatively minor if compared with those associated with the Himalayas and Alps, a characteristics related to the high integrated strength of the North American craton. Despite the generally little deformation of the continental interior, two regional-scale tectonic features preserved evidence of significant Paleozoic tectonism: the fault bounded Hudson Bay Central High (HBCH) and the Boothia uplift/Cornwallis fold belt (BUCF) in the Canadian Arctic. In the Hudson Bay intracratonic basin, the lower part of the sedimentary succession (Upper Ordovician to Lower Devonian) is cut by high-angle faults and overlain by a saucer-shape, essentially underformed sedimentary package (Middle to Upper Devonian). The main structural feature is the NNW-trending HBCH that extends for a minimum length of 500 km with normal faults characterized by throws up to 500 m that were mainly active during the Silurian - Early Devonian period. The >700-km long, N-trending BUCF is nearly perpendicular to the deformation front of the Franklinian mobile belt. In its southern segment (Boothia uplift), its western side is characterized by an east-dipping reverse fault zone that puts Precambrian rocks over Paleozoic strata. In its northern segment (Cornwallis fold belt), the Paleozoic succession is involved in open folds and cuts by steeply dipping reverse faults. Syn-tectonic clastic sediments constrain the age of structures to the latest Silurian-Early Devonian. Comparison of the HBCH and BUCF indicates that they are grossly parallel, partly contemporaneous but with different kinematics. This kinematic variability may be explained if they are genetically linked with different segments of

  6. Absolute Plate Velocities from Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Zheng, Lin; Gordon, Richard

    2015-04-01

    The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental

  7. National Cry for Help: Psychological Issues as They Relate to Education; A Realistic Approach to Understanding and Coping with the African American Males

    ERIC Educational Resources Information Center

    Anthony, Taiwanna D.; Kritsonis, William Allan; Herrington, David E.

    2007-01-01

    One could argue that advance teacher training does not make a difference in student achievement. According to William Sanders, a Professor at the University of Tennessee, the single most dominate factor affecting student achievement gain is teachers advance training. African American students make up 17 percent of the public school population…

  8. LEADERSHIP TRAINING PROGRAM FOR SELECTED AFRICAN HEALTH SPECIALISTS (WASHINGTON, D.C., SEPTEMBER 12-24, 1965). APPLICATIONS OF HUMAN RELATIONS LABORATORY TRAINING, NUMBER 3, 1966.

    ERIC Educational Resources Information Center

    MIAL, H. CURTIS

    THE AGENCY FOR INTERNATIONAL DEVELOPMENT HAS BEEN TRAINING AFRICAN HEALTH SPECIALISTS IN THE UNITED STATES, BUT LEADERSHIP TRAINING HAS BEEN GIVEN LITTLE ATTENTION. SUCH TRAINING SHOULD HELP THEM OVERCOME DIFFERENCES BETWEEN MODERN TECHNOLOGY AND TRADITIONAL CUSTOMS, DEFINE ORGANIZATIONAL ROLE, RESOLVE STATUS DIFFERENCES, AND GET COOPERATIVE…

  9. Explaining Disproportionately High Rates of Adverse Birth Outcomes among African Americans: The Impact of Stress, Racism, and Related Factors in Pregnancy

    ERIC Educational Resources Information Center

    Giscombe, Cheryl L.; Lobel, Marci

    2005-01-01

    Compared with European Americans, African American infants experience disproportionately high rates of low birth weight and preterm delivery and are more than twice as likely to die during their 1st year of life. The authors examine 5 explanations for these differences in rates of adverse birth outcomes: (a) ethnic differences in health behaviors…

  10. Frederick Douglass and I: Writing to Read and Relate History with Life among African American Adolescents at a High-Poverty Urban School

    ERIC Educational Resources Information Center

    Morphy, Paul

    2013-01-01

    Purpose: Black history as represented in social studies textbooks often lacks depth demanded by historians and authenticity required for cultural relevance to African American students. However, important Black historical narratives sometimes contain difficult prose and refer to times or circumstances that are far removed from students' life…

  11. Self Regulated and Communal Learning Contexts as They Relate to Math Achievement and Math Self Efficacy among African American Elementary Level Students

    ERIC Educational Resources Information Center

    Jackson, Shirley Faye Jackson

    2012-01-01

    For decades, African American students, nationwide, have consistently scored much lower on math and reading achievement tests than their European counterparts, creating what is known as the "White-Black Achievement Gap". The purpose of the research was to determine if self regulated learning and communal learning contexts, either…

  12. Factors Related to Self-Esteem among African American Youths: A Secondary Analysis of the High/Scope Perry Preschool Data.

    ERIC Educational Resources Information Center

    Luster, Tom; McAdoo, Harriette Pipes

    1995-01-01

    Used Perry Preschool data on 121 African American adolescents to explore correlates of self-esteem. Higher self-esteem scores were expected for youths who had experienced success in areas important to them and who perceived that significant others regarded them highly. Data supported the hypothesis that the effects of teens' accomplishments and…

  13. A Comparative Analysis Regarding Factors Related to 13- to 18-Year-Old African American Male Adolescents in Special Education and the Justice System

    ERIC Educational Resources Information Center

    Phipps, Jonathan Lanier

    2013-01-01

    This study was focused on the identification of selected risk factors seemingly present among African American male adolescents 13 to 18 years old who were participants in special education programs at their schools. Many of these male adolescents were also found to participate in the juvenile justice system under what was characterized as…

  14. China's Recruitment of African University Students: Policy Efficacy and Unintended Outcomes

    ERIC Educational Resources Information Center

    Haugen, Heidi Østbø

    2013-01-01

    This article explores how Sino-African relations are affected by the growing number of Africans who pursue higher education in China. China actively recruits African university students in order to increase soft power and generate income from the export of education services. Semi-structured interviews with African university students suggest that…

  15. In situ rutile petrochronology: texture-related T, Paleoproterozoic inheritance and a Pan-African overprint in the oldest subduction-related eclogites, Usagaran Orogen, Tanzania

    NASA Astrophysics Data System (ADS)

    Moeller, A.; Kraus, K.; Herms, P.; Appel, P.; Raase, P.

    2014-12-01

    Rutile U-Pb thermochronology is applied successfully by both TIMS and beam methods to date cooling events in mafic and metapelitic rocks, as well as in detrital studies. The Zr-in-rutile thermometer is very robust to thermal diffusion, and generally requires complete recrystallization to change recorded crystallization temperatures. Evidence for diffusion of HFSE elements in rutile is sparse; whereas U-Pb chronology generally records diffusion controlled cooling from the last event. This study follows conventional thermobarometry and U-Pb TIMS results on monazite, sphene and rutile of Möller et al. (1995) establishing a 2 Ga eclogite facies event from MORB-like metabasic, and metapelitic rocks in the Usagaran Orogen of Tanzania, interpreted to be the oldest outcrops of subduction-related eclogites. Rutile from both rock types were discordant near a ca. 500 Ma lower intercept, confirming a thermal overprint postulated on the basis of K-Ar and Rb-Sr mica ages by e.g. Wendt et al. (1972). The age of the eclogite-facies event was confirmed by U-Pb zircon dating of a 1991±2 Ma crosscutting pegmatite (Collins et al., 1999). We present in situ LA-ICP-MS rutile petrochronology on five metabasic and metapelitic eclogite facies samples with variable retrograde amphibolite-facies recrystallization. Thermometry confirms conventional Fe-Mg results, including higher peak temperatures in metabasites. Traverses on rutile inclusions in large garnet prophyroblasts in metapelites show increasing temperatures from cores outwards and a slight decrease towards outermost rims, with peak T coinciding with highest Mg# and highest grossular content, hence consistent with preservation of prograde zoning in the garnets and a brief eclogite facies event. Large rutiles (800μm) in recrystallized samples record temperature zoning profiles. U-Pb results show inheritance of near concordant 2 Ga domains, but dominantly confirm the ca. 490 Ma amphibolite facies overprint. The study is an excellent

  16. The African Cultural Astronomy Project

    NASA Astrophysics Data System (ADS)

    Urama, Johnson O.; Holbrook, Jarita C.

    2011-06-01

    Indigenous, endogenous, traditional, or cultural astronomy focuses on the many ways that people and cultures interact with celestial bodies. In most parts of Africa, there is very little or no awareness about modern astronomy. However, like ancient people everywhere, Africans wondered at the sky and struggled to make sense of it. The African Cultural Astronomy Project aims to unearth the body of traditional knowledge of astronomy possessed by peoples of the different ethnic groups in Africa and to consider scientific interpretations when appropriate for cosmogonies and ancient astronomical practices. Regardless of scientific validity, every scientist can relate to the process of making observations and creating theoretical mechanisms for explaining what is observed. Through linking the traditional and the scientific, it is believed that this would be used to create awareness and interest in astronomy in most parts of Africa. This paper discusses the vision, challenges and prospects of the African Cultural Astronomy Project in her quest to popularize astronomy in Africa.

  17. African Americans and Glaucoma

    MedlinePlus

    ... Involved News About Us Donate In This Section African Americans and Glaucoma email Send this article to a ... glaucoma is the leading cause of blindness in African Americans. Half of those with glaucoma don't know ...

  18. Black African Traditional Mathematics

    ERIC Educational Resources Information Center

    Zaslavsky, Claudia

    1970-01-01

    Discusses the traditional number systems and the origin of the number names used by several African peoples living south of the Sahara. Also included are limitations in African mathematical development, and possible topics for research. (RP)

  19. Wellness among African American Counselors

    ERIC Educational Resources Information Center

    Day-Vines, Norma L.; Holcomb-McCoy, Cheryl

    2007-01-01

    Although there are various definitions of wellness, few conceptual definitions have addressed the contextual dimensions of wellness relative to African American counselors. The authors present an overview of generic models of wellness, discuss factors that both inhibit and promote wellness, offer some culture-specific models of wellness, and…

  20. Informing cancer prevention strategies for African Americans: the relationship of African American acculturation to fruit, vegetable, and fat intake.

    PubMed

    Ard, Jamy D; Skinner, Celette Sugg; Chen, Chuhe; Aickin, Mikel; Svetkey, Laura P

    2005-06-01

    Acculturation has been associated with health-related behaviors in African Americans. We sought to determine if there is a relationship between acculturation and dietary intake in African Americans. African Americans in the PREMIER trial completed the African American Acculturation Scale (AAAS) and 2 nonconsecutive 24-h dietary recalls (n = 238). Analysis of variance (ANOVA) and canonical correlation were used to assess relationships between acculturation and dietary intakes. Canonical correlation (p = 0.05) showed that traditional African Americans had lower intakes of fruits/vegetables and milk/dairy with higher intakes of fats, meat, and nuts. This pattern was supported by differences in the ANOVA. African American acculturation is related to dietary intake. These findings have implications for the design of cancer-related public health messages targeted to African Americans.

  1. Role of mantle flow in Nubia-Somalia plate divergence

    NASA Astrophysics Data System (ADS)

    Stamps, D. S.; Iaffaldano, G.; Calais, E.

    2015-01-01

    Present-day continental extension along the East African Rift System (EARS) has often been attributed to diverging sublithospheric mantle flow associated with the African Superplume. This implies a degree of viscous coupling between mantle and lithosphere that remains poorly constrained. Recent advances in estimating present-day opening rates along the EARS from geodesy offer an opportunity to address this issue with geodynamic modeling of the mantle-lithosphere system. Here we use numerical models of the global mantle-plates coupled system to test the role of present-day mantle flow in Nubia-Somalia plate divergence across the EARS. The scenario yielding the best fit to geodetic observations is one where torques associated with gradients of gravitational potential energy stored in the African highlands are resisted by weak continental faults and mantle basal drag. These results suggest that shear tractions from diverging mantle flow play a minor role in present-day Nubia-Somalia divergence.

  2. Impact on multilayered composite plates

    NASA Technical Reports Server (NTRS)

    Kim, B. S.; Moon, F. C.

    1977-01-01

    Stress wave propagation in a multilayer composite plate due to impact was examined by means of the anisotropic elasticity theory. The plate was modelled as a number of identical anisotropic layers and the approximate plate theory of Mindlin was then applied to each layer to obtain a set of difference-differential equations of motion. Dispersion relations for harmonic waves and correction factors were found. The governing equations were reduced to difference equations via integral transforms. With given impact boundary conditions these equations were solved for an arbitrary number of layers in the plate and the transient propagation of waves was calculated by means of a Fast Fourier Transform algorithm. The multilayered plate problem was extended to examine the effect of damping layers present between two elastic layers. A reduction of the interlaminar normal stress was significant when the thickness of damping layer was increased but the effect was mostly due to the softness of the damping layer. Finally, the problem of a composite plate with a crack on the interlaminar boundary was formulated.

  3. The African Connection

    ERIC Educational Resources Information Center

    Oguntoyinbo, Lekan

    2012-01-01

    From student and faculty exchanges to joint research projects, U.S. universities maintain a broad spectrum of collaborative relationships with African universities. It's unclear how many U.S. colleges and universities have partnerships with African universities. The African Studies Association, an organization of scholars, doesn't keep that kind…

  4. Evolution of Eocene to Oligocene arc-related volcanism in the North Patagonian Andes (39-41°S), prior to the break-up of the Farallon plate

    NASA Astrophysics Data System (ADS)

    Iannelli, Sofía B.; Litvak, Vanesa D.; Fernández Paz, Lucía; Folguera, Andrés; Ramos, Miguel E.; Ramos, Víctor A.

    2017-01-01

    Voluminous Paleogene magmatic rocks (44 to 29 Ma) are found in a retroarc position in the Northern Patagonian to Southern Central Andes ( 39-42°S), whose origin remains controversial. Geochemical data in these Eocene to Oligocene volcanic associations are herein used to unravel their origin and understand changes in subduction parameters. Geochemical signatures indicate arc-related associations and reflect changing geodynamic boundary conditions of the Andean margin through time. In particular, Eocene magmatism ( 44 Ma; Pilcaniyeu Belt) shows an alkaline-like signature and limited slab influence. Reported contemporaneous within-plate magmatism ( 47-43 Ma) in an easternmost position reflects a more typical enriched source. Oligocene arc-like volcanism ( 29 Ma; El Maitén Belt), which developed in an extensional retroarc setting, shows a higher contribution from slab-derived fluids and a calc-alkaline source. A comparison with younger arc-related magmas from the region ( 26-20 Ma), emplaced in an intra- to retroarc position (Cura Mallín and Abanico basins), indicates a progressive increase in slab-signature, associated with a tholeiitic magma source. We propose that these compositional variations could be directly related to changes in plate configuration before and after the Farallon plate break-up and the initiation of a more orthogonal convergence typical of the present Andean-type subduction zone.

  5. An Ambivalent Community: International African Students in Residence at a South African University

    ERIC Educational Resources Information Center

    Weber, Everard

    2016-01-01

    This is a qualitative case study of the experiences and perceptions of South African and especially international, African students living in university residences in South Africa. The concept, community, is used to interpret interview data. This community was characterised by ambivalent social relations: There was discrimination by South Africans…

  6. Changing Fatherhood: An Exploratory Qualitative Study with African and African Caribbean Men in England

    ERIC Educational Resources Information Center

    Williams, Robert; Hewison, Alistair; Wildman, Stuart; Roskell, Carolyn

    2013-01-01

    This paper presents findings from a qualitative study undertaken with 46 African and African Caribbean men exploring their experiences of fatherhood. Data analysis was informed by Connell's theoretical work on changing gender relations. Findings indicate that fathers' lives were mediated by masculinities, racism, gender, migration and generational…

  7. Tethyan collision forces and the stress field of the Eurasian Plate

    NASA Astrophysics Data System (ADS)

    Warners-Ruckstuhl, Karin N.; Govers, Rob; Wortel, Rinus

    2013-10-01

    Resistive forces along convergent plate boundaries have a major impact on surface deformation, most visibly at collisional plate boundaries. Although quantification of these forces is key to understanding the evolution and present state of mountain belts, they remain highly uncertain due to the complexity of plate boundary structures and rheologies. In previous studies of the Eurasian Plate, we have analysed the balance of plate boundary forces, tractions resulting from lithosphere-mantle coupling, and intraplate variations in topography and density structure. This yielded a range of acceptable force distributions. In this study, we investigate to which extent the observed present-day stress field provides further constraints on the distribution of forces. We address the dynamics of the Eurasian Plate as a whole. This enables us to base our analysis on mechanical equilibrium of a tectonic plate and to evaluate all forces as part of an internally consistent set of forces driving and deforming Eurasia. We incorporate tractions from convective mantle flow modelling in a lithospheric model in which edge and lithospheric body forces are modelled explicitly and compute resulting stresses in a homogeneous elastic thin shell. Intraplate stress observations used are from the World Stress Map project. Eurasia's stress field turns out to be particularly sensitive to the distribution of collision forces on the plate's southern margin and, to a much lesser extent, to lithospheric density structure and tractions from mantle flow. Stress observations require collision forces on the India-Eurasia boundary of 7.0-10.5 TN m-1 and on the Arabia-Eurasia boundary of 1.3-2.7 TN m-1. Implication of mechanical equilibrium of the plate is that forces on the contacts with the African and Australian plates amount to 1.0-2.5 and 0-1.3 TN m-1, respectively. We use our results to assess the validity of the classical view that the mean elevation of an orogenic plateau can be taken as a measure

  8. A Comparison of Phenotypic Traits Related to Trypanotolerance in Five West African Cattle Breeds Highlights the Value of Shorthorn Taurine Breeds

    PubMed Central

    Berthier, David; Peylhard, Moana; Dayo, Guiguigbaza-Kossigan; Flori, Laurence; Sylla, Souleymane; Bolly, Seydou; Sakande, Hassane; Chantal, Isabelle; Thevenon, Sophie

    2015-01-01

    Background Animal African Trypanosomosis particularly affects cattle and dramatically impairs livestock development in sub-Saharan Africa. African Zebu (AFZ) or European taurine breeds usually die of the disease in the absence of treatment, whereas West African taurine breeds (AFT), considered trypanotolerant, are able to control the pathogenic effects of trypanosomosis. Up to now, only one AFT breed, the longhorn N’Dama (NDA), has been largely studied and is considered as the reference trypanotolerant breed. Shorthorn taurine trypanotolerance has never been properly assessed and compared to NDA and AFZ breeds. Methodology/Principal Findings This study compared the trypanotolerant/susceptible phenotype of five West African local breeds that differ in their demographic history. Thirty-six individuals belonging to the longhorn taurine NDA breed, two shorthorn taurine Lagune (LAG) and Baoulé (BAO) breeds, the Zebu Fulani (ZFU) and the Borgou (BOR), an admixed breed between AFT and AFZ, were infected by Trypanosoma congolense IL1180. All the cattle were genetically characterized using dense SNP markers, and parameters linked to parasitaemia, anaemia and leukocytes were analysed using synthetic variables and mixed models. We showed that LAG, followed by NDA and BAO, displayed the best control of anaemia. ZFU showed the greatest anaemia and the BOR breed had an intermediate value, as expected from its admixed origin. Large differences in leukocyte counts were also observed, with higher leukocytosis for AFT. Nevertheless, no differences in parasitaemia were found, except a tendency to take longer to display detectable parasites in ZFU. Conclusions We demonstrated that LAG and BAO are as trypanotolerant as NDA. This study highlights the value of shorthorn taurine breeds, which display strong local adaptation to trypanosomosis. Thanks to further analyses based on comparisons of the genome or transcriptome of the breeds, these results open up the way for better knowledge

  9. Large artery stiffness and carotid intima-media thickness in relation to markers of calcium and bone mineral metabolism in African women older than 46 years.

    PubMed

    Gafane, L F; Schutte, R; Kruger, I M; Schutte, A E

    2015-03-01

    Vascular calcification and cardiovascular diseases have been associated with altered bone metabolism. We explored the relationships of arterial pressures and carotid intima-media thickness (CIMT) with parathyroid hormone, 25-hydroxycholecalciferol and their ratio (PTH:25(OH)D3) as well as a marker of bone resorption (CTX) in lean and overweight/obese African women. A population of 434 African women older than 46 years was divided into lean and overweight/obese groups. We assessed brachial blood pressure, central pulse pressure (cPP) and CIMT, and determined PTH, 25(OH)D3 and CTX concentrations. Overweight/obese women had elevated PTH and PTH:25(OH)D3 compared with lean women (both P<0.001), whereas lean women had higher CTX (P<0.001). Single, partial and multiple regression analyses indicated that, in lean women CIMT was independently associated with PTH:25(OH)D3 (R(2)=0.22; β=0.26; P=0.003), whereas in obese women cPP was associated with both PTH:25(OH)D3 (R2=0.20; β=0.17; P=0.017) and CTX (R2=0.20; β=0.17; P=0.025). In conclusion, we found that in African women with increased adiposity, cPP (as a surrogate measure of arterial stiffness), was positively associated with alterations in bone metabolism and calciotropic hormones, whereas CIMT of lean women was positively associated with PTH:25(OH)D3. Our results suggest that alterations in bone and calcium metabolism may contribute to arterial calcification in older African women.

  10. Provenance change of sediment input in the northeastern foreland of Pamir related to collision of the Indian Plate with the Kohistan-Ladakh arc at around 47 Ma

    NASA Astrophysics Data System (ADS)

    Sun, Jimin; Xiao, Wenjiao; Windley, Brian F.; Ji, Weiqiang; Fu, Bihong; Wang, Jiangang; Jin, Chunsheng

    2016-02-01

    The Pamir plateau forms a prominent tectonic salient that marks the western end of the Himalayan orogen containing several terranes that were accreted to Eurasia from the Late Paleozoic to Cenozoic. A detailed knowledge of the tectonic evolution of the Pamir salient during the Cenozoic is important for our understanding of the intracontinental deformation in the western Himalaya. Although the tectonic evolution of the Pamir salient has long been studied, the timing of collision between the Indian Plate and the Kohistan-Ladakh arc is still a matter of debate. We present new U-Pb ages and Hf isotopes of detrital zircons, magnetic fabrics, and stable isotopes from the foreland basin on the northeastern margin of the Pamir that indicate a change in sediment provenance started at about 47 Ma. Sediments in the southwest Tarim Basin were partially derived from the uplifted and eroded Karakoram and Kohistan terranes created by the collision between the Indian Plate and the Kohistan-Ladakh arc at circa 47 Ma, as a result of northward thrusting and propagation of the Indian Plate under Eurasia.

  11. Using the Mesozoic History of the Canadian Cordillera as a Case Study in Teaching Plate Tectonics.

    ERIC Educational Resources Information Center

    Chamberlain, Valerie Elaine

    1989-01-01

    Reviews a model used in the teaching of plate tectonics which includes processes and concepts related to: terranes and the amalgamation of terranes, relative plate motion and oblique subduction, the effects of continent-continent collision, changes in plate motion, plate configuration, and the type of plate boundary. Diagrams are included.…

  12. An understanding of HSLA-65 plate steels

    NASA Astrophysics Data System (ADS)

    Sampath, K.

    2006-02-01

    HSLA-65 plate steels can be produced using one of five plate manufacturing techniques: normalizing, controlled rolling (CR), controlled rolling followed by accelerated cooling (CR-AC), direct quenching and tempering (DQT), or conventional quenching and tempering (Q&T). The HSLA-65 steels are characterized by low carbon content and low alloy content, and they exhibit a low carbon equivalent that allows improved plate weldability. These characteristics in turn (a) provide the steel plate with a refined microstructure that ensures high strength and toughness; (b) eliminate or substantially reduce the need for preheating during welding; (c) resist susceptibility to hydrogen-assisted cracking (HAC) in the weld heat affected zone (HAZ) when fusion (arc) welded using low heat-input conditions; and (d) depending on section thickness, facilitate high heat-input welding (about 2 kJ/mm) without significant loss of strength or toughness in the HAZ. However, application of this plate manufacturing process and of these controls produces significant differences in the metallurgical structure and range of mechanical properties of the HSLA-65 plate steels both among themselves and versus conventional higher strength steel (HSS) plates. For example, among the HSLA-65 plate steels, those produced by Q&T exhibit minimal variability in mechanical properties, especially in thicker plates. Besides variability in mechanical properties depending on plate thickness, the CR and CR-AC plate steels exhibit a relatively higher yield strength to ultimate tensile strength (YS/UTS) ratio than do DQT and Q&T steels. Such differences in processing and properties of HSLA-65 plate steels could potentially affect the selection and control of various secondary fabrication practices, including arc welding. Consequently, fabricators must exercise extreme caution when transferring allowable limits of certified secondary fabrication practices from one type of HSLA-65 plate steel to another, even for the

  13. How do we measure up? A comparison of lifestyle-related health risk factors among sampled employees in South African and UK companies.

    PubMed

    Milner, Karen; da Silva, Roseanne; Patel, Deepak; Salau, Sulaiman

    2016-07-12

    The need to address the growing prevalence of non-communicable diseases through changing the lifestyle behaviours that contribute to them has become a global priority. Settings-based health promotion strategies such as workplace health promotion programmes are growing in an attempt to start meeting this need. In order for settings-based health promotion programmes to be successful, they need to be based on the specific risk profiles of the population for whom they are designed. Workplace health promotion programmes are becoming popular in South Africa, but there are currently few data available about the health risks and lifestyle behaviours of the South African employed population. In order to obtain such data and reward workplace health promotion initiatives, Discovery Health initiated healthy company campaigns in South Africa and the UK. These campaigns took the form of a competition to assess the healthiest companies in each country. Through these campaigns, an extensive data set was collected encompassing UK and South African employees' lifestyle behaviours and health risks. In this article, we used these data to compare self-reported physical activity levels, self-reported fruit and vegetable consumption, calculated BMI, self-reported smoking, mental health indicators, and health screening status of the UK and South African employee samples. We found significant differences across all measures, with the exception of self-reported fruit and vegetable consumption. The findings emphasise the importance of using local data to tailor workplace health promotion programmes for the population for which the programmes have been designed.

  14. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  15. Closure of the Africa-Eurasia-North America plate motion circuit and tectonics of the Gloria fault

    NASA Technical Reports Server (NTRS)

    Argus, Donald F.; Gordon, Richard G.; Demets, Charles; Stein, Seth

    1989-01-01

    The current motions of the African, Eurasian, and North American plates are examined. The problems addressed include whether there is resolvable motion of a Spitsbergen microplate, the direction of motion between the African and North American plates, whether the Gloria fault is an active transform fault, and the implications of plate circuit closures for rates of intraplate deformation. Marine geophysical data and magnetic profiles are used to construct a model which predicts about 4 mm/yr slip across the Azores-Gibraltar Ridge, and west-northwest convergence near Gibraltar. The analyzed data are consistent with a rigid plate model with the Gloria fault being a transform fault.

  16. Eastern segment of the Azores-Gibraltar line (central-eastern Atlantic) : An oceanic plate boundary with diffuse compressional deformation

    NASA Astrophysics Data System (ADS)

    Sartori, R.; Torelli, L.; Zitellini, N.; Peis, D.; Lodolo, E.

    1994-06-01

    New seismic-reflection images across the eastern segment of the Azores-Gibraltar line west of the collisional area between the African and Iberian plates have revealed a complex pattern of compressional deformation involving the Mesozoic oceanic lithosphere. The compressional deformation developed in a region of slow plate convergence and is diffused, at different lithospheric levels, across an area spanning ˜200 km from the Gorringe Ridge to the Seine Plain. The convergence between the African and Iberian plates has been active since Tertiary time, and our results indicate that no subduction zone exists across this part of the plate boundary.

  17. Kinematics of a former oceanic plate of the Neotethys revealed by deformation in the Ulukışla basin (Turkey)

    NASA Astrophysics Data System (ADS)

    Gürer, Derya; Hinsbergen, Douwe J. J.; Matenco, Liviu; Corfu, Fernando; Cascella, Antonio

    2016-10-01

    Kinematic reconstruction of modern ocean basins shows that since Pangea breakup a vast area in the Neotethyan realm was lost to subduction. Here we develop a first-order methodology to reconstruct the kinematic history of the lost plates of the Neotethys, using records of subducted plates accreted to (former) overriding plates, combined with the kinematic analysis of overriding plate extension and shortening. In Cretaceous-Paleogene times, most of Anatolia formed a separate tectonic plate—here termed "Anadolu Plate"—that floored part of the Neotethyan oceanic realm, separated from Eurasia and Africa by subduction zones. We study the sedimentary and structural history of the Ulukışla basin (Turkey); overlying relics of this plate to reconstruct the tectonic history of the oceanic plate and its surrounding trenches, relative to Africa and Eurasia. Our results show that Upper Cretaceous-Oligocene sediments were deposited on the newly dated suprasubduction zone ophiolites ( 92 Ma), which are underlain by mélanges, metamorphosed and nonmetamorphosed oceanic and continental rocks derived from the African Plate. The Ulukışla basin underwent latest Cretaceous-Paleocene N-S and E-W extension until 56 Ma. Following a short period of tectonic quiescence, Eo-Oligocene N-S contraction formed the folded structure of the Bolkar Mountains, as well as subordinate contractional structures within the basin. We conceptually explain the transition from extension, to quiescence, to shortening as slowdown of the Anadolu Plate relative to the northward advancing Africa-Anadolu trench resulting from collision of continental rocks accreted to Anadolu with Eurasia, until the gradual demise of the Anadolu-Eurasia subduction zone.

  18. Obliquity along plate boundaries

    NASA Astrophysics Data System (ADS)

    Philippon, Mélody; Corti, Giacomo

    2016-12-01

    Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundaries total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries that are not perpendicular but oblique to the direction of far field stresses. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.

  19. Plating Tank Control Software

    SciTech Connect

    Krafcik, John

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  20. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  1. Bioenergy and African transformation.

    PubMed

    Lynd, Lee R; Sow, Mariam; Chimphango, Annie Fa; Cortez, Luis Ab; Brito Cruz, Carlos H; Elmissiry, Mosad; Laser, Mark; Mayaki, Ibrahim A; Moraes, Marcia Afd; Nogueira, Luiz Ah; Wolfaardt, Gideon M; Woods, Jeremy; van Zyl, Willem H

    2015-01-01

    Among the world's continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures.

  2. Beyond plate tectonics - Looking at plate deformation with space geodesy

    NASA Technical Reports Server (NTRS)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  3. Social motility in African trypanosomes: fact or model?

    PubMed

    Bastin, Philippe; Rotureau, Brice

    2015-02-01

    African trypanosomes grown on agarose plates exhibit behaviours akin to social motility. This phenomenon has not been observed in vivo so far but recently turned out to be instrumental in the definition of two specific stages of the parasite cycle and as a tool to probe for trypanosome sensing functions.

  4. Kinematics of the Ethiopian Rift and Absolute motion of Africa and Somalia Plates

    NASA Astrophysics Data System (ADS)

    Muluneh, A. A.; Cuffaro, M.; Doglioni, C.

    2013-12-01

    The Ethiopian Rift (ER), in the northern part of East African Rift System (EARS), forms a boundary zone accommodating differential motion between Africa and Somalia Plates. Its orientation was influenced by the inherited Pan-African collisional system and related lithospheric fabric. We present the kinematics of ER derived from compilation of geodetic velocities, focal mechanism inversions, structural data analysis, and construction of geological profiles. GPS velocity field shows a systematic eastward magnitude increase in NE direction in the central ER. In the same region, incremental extensional strain axes recorded by earthquake focal mechanism and fault slip inversion show ≈N1000E orientation. This deviation between GPS velocity trajectories and orientation of incremental extensional strain is developed due to left lateral transtensional deformation. This interpretation is consistent with the en-échelon pattern of tensional and transtensional faults, the distribution of the volcanic centers, and the asymmetry of the rift itself. Small amount of vertical axis blocks rotation, sinistral strike slip faults and dyke intrusions in the rift accommodate the transtensional deformation. We analyzed the kinematics of ER relative to Deep and Shallow Hot Spot Reference Frames (HSRF). Comparison between the two reference frames shows different kinematics in ER and also Africa and Somalia plate motion both in magnitude and direction. Plate spreading direction in shallow HSRF (i.e. the source of the plumes locates in the asthenosphere) and the trend of ER deviate by about 27°. Shearing and extension across the plate boundary zone contribute both to the style of deformation and overall kinematics in the rift. We conclude that the observed long wavelength kinematics and tectonics are consequences of faster SW ward motion of Africa than Somalia in the shallow HSRF. This reference frame seems more consistent with the geophysical and geological constraints in the Rift. The

  5. Incorporating Cutting Edge Scientific Results from the Margins-Geoprisms Program into the Undergraduate Curriculum, Rupturing Continental Lithosphere Part II: Introducing Euler Poles Using Baja-North America Relative Plate Motion Across the Gulf of California

    NASA Astrophysics Data System (ADS)

    Loveless, J. P.; Bennett, S. E. K.; Cashman, S. M.; Dorsey, R. J.; Goodliffe, A. M.; Lamb, M. A.

    2014-12-01

    The NSF-MARGINS Program funded a decade of research on continental margin processes. The NSF-GeoPRISMS Mini-lesson Project, funded by NSF-TUES, is designed to integrate the significant findings from the MARGINS program into open-source college-level curriculum. The Gulf of California (GOC) served as the focus site for the Rupturing Continental Lithosphere (RCL) initiative, which addressed several scientific questions: What forces drive rift initiation, localization, propagation and evolution? How does deformation vary in time and space, and why? How does crust evolve, physically and chemically, as rifting proceeds to sea-floor spreading? What is the role of sedimentation and magmatism in continental extension? We developed two weeks of curriculum, including lectures, labs, and in-class activities that can be used as a whole or individually. This component of the curriculum introduces students to the Euler pole description of relative plate motion (RPM) by examining the tectonic interactions of the Baja California microplate and North American plate. The plate boundary varies in rift obliquity along strike, from highly oblique and strike-slip dominated in the south to slightly less oblique and with a larger extensional component in the north. This Google Earth-based exercise provides students with a visualization of RPM using small circle contours of the local direction and magnitude of Baja-North America movement on a spherical Earth. Students use RPM to calculate the fault slip rates on transform, normal, and oblique-slip faults and examine how the varying faulting styles combine to accommodate RPM. MARGINS results are integrated via comparison of rift obliquity with the structural style of rift-related faults around the GOC. We find this exercise to fit naturally into courses about plate tectonics, geophysics, and especially structural geology, given the similarity between Euler pole rotations and stereonet-based rotations of structural data.

  6. Were aspects of Pan-African deformation linked to Iapetus opening?

    NASA Astrophysics Data System (ADS)

    Grunow, Anne; Hanson, Richard; Wilson, Terry

    1996-12-01

    The convergence recorded in some Pan-African deformational belts (sensu lato) in South America, Africa, Madagascar, southern India, Sri Lanka, and Antarctica is temporally correlated with opening of the Iapetus ocean. We propose a model in which continent-continent collision and closure of the Adamastor ocean between the Amazon West African Rio de La Plata cratons and the São Francisco Congo Kalahari cratons in the late Neoproterozoic are linked to rifting and orthogonal spreading between Laurentia and the South American cratons. By the Early Cambrian, the cratons in South America and Africa were assembled as West Gondwana. Closure of the Mozambique ocean, which appears to have extended across Antarctica between Lützow-Holm Bay and the Shackleton Range, resulted in continued convergence between the Congo Kalahari Queen Maud Land block and East Gondwana in the Cambrian. Coeval deformation in the Transantarctic Mountains may be related to the obliquity of the Antarctic margin relative to Iapetus spreading directions. Initiation of voluminous arc magmatism along the paleo-Pacific margin of Gondwana in the Early Cambrian is broadly synchronous with the cessation of intra-Gondwana Pan-African deformation, possibly reflecting a change in plate motions at the time of final Gondwana assembly. The new subduction regime along the Gondwana margin in the Early Cambrian may be linked to the closure of the Iapetus ocean basin.

  7. Coupling between plate vibration and acoustic radiation

    NASA Technical Reports Server (NTRS)

    Frendi, Abdelkader; Maestrello, Lucio; Bayliss, Alvin

    1992-01-01

    A detailed numerical investigation of the coupling between the vibration of a flexible plate and the acoustic radiation is performed. The nonlinear Euler equations are used to describe the acoustic fluid while the nonlinear plate equation is used to describe the plate vibration. Linear, nonlinear, and quasi-periodic or chaotic vibrations and the resultant acoustic radiation are analyzed. We find that for the linear plate response, acoustic coupling is negligible. However, for the nonlinear and chaotic responses, acoustic coupling has a significant effect on the vibration level as the loading increases. The radiated pressure from a plate undergoing nonlinear or chaotic vibrations is found to propagate nonlinearly into the far-field. However, the nonlinearity due to wave propagation is much weaker than that due to the plate vibrations. As the acoustic wave propagates into the far-field, the relative difference in level between the fundamental and its harmonics and subharmonics decreases with distance.

  8. Coupling between plate vibration and acoustic radiation

    NASA Technical Reports Server (NTRS)

    Frendi, Abdelkader; Maestrello, Lucio; Bayliss, Alvin

    1993-01-01

    A detailed numerical investigation of the coupling between the vibration of a flexible plate and the acoustic radiation is performed. The nonlinear Euler equations are used to describe the acoustic fluid while the nonlinear plate equation is used to describe the plate vibration. Linear, nonlinear, and quasi-periodic or chaotic vibrations and the resultant acoustic radiation are analyzed. We find that for the linear plate response, acoustic coupling is negligible. However, for the nonlinear and chaotic responses, acoustic coupling has a significant effect on the vibration level as the loading increases. The radiated pressure from a plate undergoing nonlinear or chaotic vibrations is found to propagate nonlinearly into the far field. However, the nonlinearity due to wave propagation is much weaker than that due to the plate vibrations. As the acoustic wave propagates into the far field, the relative difference in level between the fundamental and its harmonics and subharmonics decreases with distance.

  9. Malachite green photosensitive plates.

    PubMed

    Solano, C

    1989-08-15

    An experimental study of the behavior of malachite green sensitized plates was carried out. The transmittance variation of the irradiated plates was taken as a parameter. It has been observed that photoreduction in the malachite green plates is present only when ammonium dichromate is added to the plates. The introduction of external electron donors does not improve the photochemical reaction. It has been determined that malachite green molecules form a weak complex with the dichromate molecules and this complex can only be destroyed photochemically. This effect can explain the limited response of the malachite green dichromated plates.

  10. An improved plating process

    NASA Technical Reports Server (NTRS)

    Askew, John C.

    1994-01-01

    An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.

  11. Multicolor printing plate joining

    NASA Technical Reports Server (NTRS)

    Waters, W. J. (Inventor)

    1984-01-01

    An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent.

  12. Gene-based analysis of the fibroblast growth factor receptor signaling pathway in relation to breast cancer in African American women: the AMBER consortium.

    PubMed

    Ruiz-Narváez, Edward A; Haddad, Stephen A; Lunetta, Kathryn L; Yao, Song; Bensen, Jeannette T; Sucheston-Campbell, Lara E; Hong, Chi-Chen; Haiman, Christopher A; Olshan, Andrew F; Ambrosone, Christine B; Palmer, Julie R

    2016-01-01

    We conducted gene-based analysis in 26 genes in the FGFR signaling pathway to identify genes carrying genetic variation affecting risk of breast cancer and the specific estrogen receptor (ER) subtypes. Tagging single-nucleotide polymorphisms (SNPs) for each gene were selected and genotyped on a customized Illumina Exome Array. Imputation was carried out using 1000 Genomes haplotypes. The analysis included 3237 SNPs in 3663 breast cancer cases (including 1983 ER-positive, and 1098 ER-negative) and 4687 controls from the African American Breast Cancer Epidemiology and Risk consortium, a collaborative project of four large studies of breast cancer in African American women (Carolina Breast Cancer Study, Black Women's Health Study, Women's Circle of Health Study, and Multiethnic Cohort). We used a multi-locus adaptive joint (AdaJoint) test to determine the association of each gene in the FGFR signaling pathway with overall breast cancer and ER subtypes. The FGF1 gene was significantly associated with risk of ER-negative breast cancer (P = 0.001). The FGFR2 gene was associated with risk of overall breast cancer (P = 0.002) and ER-positive breast cancer (P = 0.002). The FGF1 gene affects risk of ER-negative breast cancer in African American women. We confirmed the association of the FGFR2 gene with risk of overall and ER-positive breast cancer. These results highlight the importance of the FGFR signaling pathway in the pathogenesis of breast cancer, and suggest that different genes in the same pathway may be associated with different ER breast cancer subtypes.

  13. Gene-based analysis of the fibroblast growth factor receptor signaling pathway in relation to breast cancer in African American women: the AMBER consortium

    PubMed Central

    Ruiz-Narváez, Edward A.; Haddad, Stephen A.; Lunetta, Kathryn L.; Yao, Song; Bensen, Jeannette T.; Sucheston-Campbell, Lara E.; Hong, Chi-Chen; Haiman, Christopher A.; Olshan, Andrew F.; Ambrosone, Christine B.; Palmer, Julie R.

    2016-01-01

    Purpose We conducted gene-based analysis in 26 genes in the FGFR signaling pathway to identify genes carrying genetic variation affecting risk of breast cancer and the specific estrogen receptor (ER) subtypes. Methods Tagging single nucleotide polymorphisms (SNPs) for each gene were selected and genotyped on a customized Illumina Exome Array. Imputation was carried out using 1000 Genomes haplotypes. The analysis included 3,237 SNPs in 3,663 breast cancer cases (including 1,983 ER positive, and 1,098 ER-negative and 4,687 controls from the African American Breast Cancer Epidemiology and Risk consortium, a collaborative project of four large studies of breast cancer in African American women (Carolina Breast Cancer Study, Black Women's Health Study, Women's Circle of Health Study, and Multiethnic Cohort). We used a multi-locus adaptive joint (AdaJoint) test to determine the association of each gene in the FGFR signaling pathway with overall breast cancer and ER subtypes. Results The FGF1 gene was significantly associated with risk of ER negative breast cancer (P = 0.001). The FGFR2 gene was associated with risk of overall breast cancer (P = 0.002) and ER positive breast cancer (P = 0.002). Conclusions The FGF1 gene affects risk of ER negative breast cancer in African American women. We confirmed the association of the FGFR2 gene with risk of overall and ER positive breast cancer. These results highlight the importance of the FGFR signaling pathway in the pathogenesis of breast cancer, and suggest that different genes in the same pathway may be associated with different ER breast cancer subtypes. PMID:26743380

  14. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  15. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  16. How rigid is a rigid plate? Geodetic constraint from the TrigNet CGPS network, South Africa

    NASA Astrophysics Data System (ADS)

    Malservisi, Rocco; Hugentobler, Urs; Wonnacott, Richard; Hackl, Matthias

    2013-03-01

    Rigidity and continuity of the Nubia plate is a fundamental assumption for the kinematic description, the dynamic implications of its interaction with surrounding plates and ultimately an important constraint to the geodynamics processes involved in continental lithospheric rupture. Geophysical, neotectonic and geodynamics considerations suggest the possibility that the Nubia plate is not completely rigid but could be undergoing internal deformation due to the southward propagation of the East African Rift. Here, we utilize the South African TrigNet geodetic network to evaluate the amount of internal deformation within the South African region and the possibility of motion between South Africa and the rest of the African continent. Our results show that the South African region behaves rigidly, with deformation of the order of 1 nanostrain yr-1 or less. The analysis shows some higher strain rates in the eastern region, and the presence of spatially correlated residuals in the Cape Town region and the region east of Johannesburg. Although not statistically significant, the spatial coherence of those residuals could indicate tectonic activity. A comparison of the Euler vector for the South African region with previously published Euler poles for the Nubia plate as well as the analysis of the residuals of Nubia sites with respect to a `rigid' TrigNet are compatible with clockwise rotation of the South African block with respect to the African continent, consistent with a propagation of the East Africa Rift along the Okavango region.

  17. Post-traumatic Stress and Trauma-Related Subjective Distress: Comparisons Among Hispanics, African-Americans, and Whites with Severe Mental Illness.

    PubMed

    O'Hare, Thomas; Shen, Ce; Sherrer, Margaret V

    2017-02-06

    We tested the hypothesis with a sample of community mental health clients (N = 132) that Hispanic clients would report significantly greater post-traumatic stress symptoms than African-American or white clients when controlling for gender, psychiatric symptoms of SMI, and subjective distress from six of the most commonly reported trauma in the SMI literature. Results supported our main hypothesis: being self-identified as Hispanic was significantly associated with greater post-traumatic stress symptoms. Subjective distress from having been sexually abused along with being "Hispanic" were the only two significant variables left in the equation. Limitations of this study include its modest sample size.

  18. African mining

    SciTech Connect

    Not Available

    1987-01-01

    This book contains papers presented at a conference addressing the development of the minerals industry in Africa. Topics covered include: A review - past, present and future - of Zimbabwe's mining industry; Geomorphological processes and related mineralization in Tanzania; and Rock mechanics investigations at Mufulira mine, Zambia.

  19. Millennial-scale northwest African droughts related to Heinrich events and Dansgaard-Oeschger cycles: Evidence in marine sediments from offshore Senegal

    NASA Astrophysics Data System (ADS)

    Itambi, A. C.; von Dobeneck, T.; Mulitza, S.; Bickert, T.; Heslop, D.

    2009-03-01

    We present a suite of new high-resolution records (0-135 ka) representing pulses of aeolian, fluvial, and biogenic sedimentation along the Senegalese continental margin. A multiproxy approach based on rock magnetic, element, and color data was applied on three cores enclosing the present-day northern limit of the ITCZ. A strong episodic aeolian contribution driven by stronger winds and dry conditions and characterized by high hematite and goethite input was revealed north of 13°N. These millennial-scale dust fluxes are synchronous with North Atlantic Heinrich stadials. Fluvial clay input driven by the West African monsoon predominates at 12°N and varies at Dansgaard-Oeschger time scales while marine productivity is strongly enhanced during the African humid periods and marine isotope stage 5. From latitudinal signal variations, we deduce that the last glacial ITCZ summer position was located between core positions at 12°26' and 13°40'N. Furthermore, this work also shows that submillennial periods of aridity over northwest Africa occurred more frequently and farther south than previously thought.

  20. INTERFACING INFANT MENTAL HEALTH KNOWLEDGE SYSTEMS: REFLECTIONS ON THE NARRATIVES OF LAY HOME VISITORS' EXPERIENCES OF LEARNING AND APPLYING RELATIONAL CONCEPTS OF DEVELOPMENT IN A SOUTH AFRICAN INTERVENTION PROGRAM.

    PubMed

    Baradon, Tessa; Bain, Katherine

    2016-07-01

    The question of interfacing research and clinically generated knowledge in the field of infant mental health (IMH) with local cultural knowledge and belief systems has provoked extended discussion in recent years. This article explores convergences and divergences between current research-based, relational IMH mental health models and "community" knowledge held by a group of South African lay home visitors from a socioeconomically deprived township. These women were trained in a psychoanalytic and attachment-informed infant mental health program that promotes a relational model of infant development. They provide an intervention that supports high risk mother-infant relationships in the same locality. A two-tiered approach was taken to the analysis of the home visitor interviews and focused on the home visitors' constructed narratives of infant development posttraining as well as the personal impact of the training and work on the home visitors themselves. The study found that psychoanalytic and attachment-informed thinking about development makes sense to those operating within the local South African cultural context, but that the accommodation of this knowledge is a complex and challenging process.

  1. Tectonics of oblique plate boundary systems

    NASA Astrophysics Data System (ADS)

    Díaz-Azpiroz, Manuel; Brune, Sascha; Leever, Karen A.; Fernández, Carlos; Czeck, Dyanna M.

    2016-12-01

    The relative displacement between lithospheric plates normally results in obliquely deforming plate boundaries. This is simply caused by the fact that, on plate tectonics basis, irregularly shaped plate boundaries are rarely perpendicular or parallel to small-circle rotation paths, which describe plate motion on a sphere (Fig. 1a). Global current relative plate motions estimated from geological data (DeMets et al., 2010; Argus et al., 2011) and GPS measurements (e.g., Kreemer et al., 2003; Argus et al., 2010) provide insight to the prevalent degrees of obliquity on Earth's surface. Based on these global data sets, Philippon and Corti (2016), statistically show that current orthogonal boundaries (obliquity angle smaller than 10°) represent around 8% of the total boundary length whereas strike-slip boundaries (obliquity angle larger than 80°) are encountered in < 10% of the total boundary length. Therefore, around 80% of active plate boundaries present oblique relative motions. Furthermore, changes in plate kinematics leading to migration or jumps in the rotation poles necessarily cause obliquity along former pure strike-slip or convergent/divergent boundaries (Fig. 1b).

  2. The African superswell

    NASA Technical Reports Server (NTRS)

    Nyblade, Andrew A.; Robinson, Scott W.

    1994-01-01

    Maps of residual bathymetry in the ocean basins around the African continent reveal a broad bathymetric swell in the southeastern Atlantic Ocean with an amplitude of about 500 m. We propose that this region of anomalously shallow bathymetry, together with the contiguous eastern and southern African plateaus, form a superswell which we refer to as the African superswell. The origin of the African superswell is uncertain. However, rifting and volcanism in eastern Africa, as well as heat flow measurements in southern Africa and the southeastern Atlantic Ocean, suggest that the superswell may be attributed, at least in part, to heating of the lithosphere.

  3. GOLD PLATING PROCESS

    DOEpatents

    Seegmiller, R.

    1957-08-01

    An improved bath is reported for plating gold on other metals. The composition of the plating bath is as follows: Gold cyanide from about 15 to about 50 grams, potassium cyanide from about 70 to about 125 grams, and sulfonated castor oil from about 0.1 to about 10 cc. The gold plate produced from this bath is smooth, semi-hard, and nonporous.

  4. Plating methods, a survey

    NASA Technical Reports Server (NTRS)

    Berkowitz, J. B.; Emerson, N. H.

    1972-01-01

    Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.

  5. "Half plate of rice to a male casual sexual partner, full plate belongs to the husband": Findings from a qualitative study on sexual behaviour in relation to HIV and AIDS in northern Tanzania

    PubMed Central

    2011-01-01

    developed in close collaboration with affected communities and be closely related to policy-making and implementation; to go beyond the limited success of traditional behavioural and biomedical interventions to particularly address the underlying social and structural drivers of HIV risk and vulnerability in the study communities. PMID:22202562

  6. PLATES WITH OXIDE INSERTS

    DOEpatents

    West, J.M.; Schumar, J.F.

    1958-06-10

    Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead.

  7. CALUTRON FACE PLATE

    DOEpatents

    Brobeck, W.M.

    1959-08-25

    The construction of a removable cover plate for a calutron tank is described. The plate is fabricated of a rectangular frame member to which is welded a bowed or dished plate of thin steel, reinforced with transverse stiffening ribs. When the tank is placed between the poles of a magnet, the plate may be pivoted away from the tank and magnet and is adapted to support the ion separation mechanism secured to its inner side as well as the vacuum load within the tank.

  8. Chronic lymphocytic leukemia in African Americans.

    PubMed

    Coombs, Catherine C; Falchi, Lorenzo; Weinberg, J Brice; Ferrajoli, Alessandra; Lanasa, Mark C

    2012-11-01

    Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in the United States with almost 4390 attributable deaths per year. Epidemiologic data compiled by the Surveillance, Epidemiology and End Results (SEER) program identifies important differences in incidence and survival for African Americans with CLL. Although the incidence of CLL is lower among African Americans than among Caucasians (4.6 and 6.2 per 100 000 men, respectively), age-adjusted survival is inferior. African American patients with CLL are almost twice as likely to die from a CLL-related complication in the first 5 years after diagnosis as are Caucasian patients with CLL. The biologic basis for these observations is almost entirely unexplored, and a comprehensive clinical analysis of African American patients with CLL is lacking. This is the subject of the present review.

  9. Differences between tuberculosis cases infected with Mycobacterium africanum, West African type 2, relative to Euro-American Mycobacterium tuberculosis: an update.

    PubMed

    de Jong, Bouke C; Adetifa, Ifedayo; Walther, Brigitte; Hill, Philip C; Antonio, Martin; Ota, Martin; Adegbola, Richard A

    2010-02-01

    Mycobacterium africanum (MAF) is a common cause of human pulmonary tuberculosis in West Africa. We previously described phenotypic differences between MAF and Mycobacterium tuberculosis (MTB) among 290 patients. In the present analysis, we compared 692 tuberculosis patients infected with the two most common lineages within the (MTB) complex found in the Gambia, namely MAF West African type 2 (39% prevalence) and Euro-American MTB (55% prevalence). We identified additional phenotypic differences between infections with these two organisms. MAF patients were more likely to be older and HIV infected. In addition, they had worse disease on chest X-ray, despite complaining of cough for an equal duration, and were more likely severely malnourished. In this cohort, the prevalence of MAF did not change significantly over a 7-year period.

  10. Spatial Structure and Climatic Adaptation in African Maize Revealed by Surveying SNP Diversity in Relation to Global Breeding and Landrace Panels

    PubMed Central

    Westengen, Ola T.; Berg, Paul R.; Kent, Matthew P.; Brysting, Anne K.

    2012-01-01

    Background Climate change threatens maize productivity in sub-Saharan Africa. To ensure food security, access to locally adapted genetic resources and varieties is an important adaptation measure. Most of the maize grown in Africa is a genetic mix of varieties introduced at different historic times following the birth of the trans-Atlantic economy, and knowledge about geographic structure and local adaptations is limited. Methodology A panel of 48 accessions of maize representing various introduction routes and sources of historic and recent germplasm introductions in Africa was genotyped with the MaizeSNP50 array. Spatial genetic structure and genetic relationships in the African panel were analysed separately and in the context of a panel of 265 inbred lines representing global breeding material (based on 26,900 SNPs) and a panel of 1127 landraces from the Americas (270 SNPs). Environmental association analysis was used to detect SNPs associated with three climatic variables based on the full 43,963 SNP dataset. Conclusions The genetic structure is consistent between subsets of the data and the markers are well suited for resolving relationships and admixture among the accessions. The African accessions are structured in three clusters reflecting historical and current patterns of gene flow from the New World and within Africa. The Sahelian cluster reflects original introductions of Meso-American landraces via Europe and a modern introduction of temperate breeding material. The Western cluster reflects introduction of Coastal Brazilian landraces, as well as a Northeast-West spread of maize through Arabic trade routes across the continent. The Eastern cluster most strongly reflects gene flow from modern introduced tropical varieties. Controlling for population history in a linear model, we identify 79 SNPs associated with maximum temperature during the growing season. The associations located in genes of known importance for abiotic stress tolerance are

  11. Addressing Reading Underachievement in African American Boys through a Multi-Contextual Approach

    ERIC Educational Resources Information Center

    Husband, Terry

    2012-01-01

    Much has been written about reading disparities between African American males and other student groups. Interestingly, the majority of this scholarship focuses on African American males at preadolescent states of development and beyond. To date, relatively little has been documented relative to improving reading outcomes in African American males…

  12. Understanding African American Males

    ERIC Educational Resources Information Center

    Bell, Edward Earl

    2010-01-01

    The purpose of this study was to assess the socialization skills, self-esteem, and academic readiness of African American males in a school environment. Discussions with students and the School Perceptions Questionnaire provided data for this investigation. The intended targets for this investigation were African American students; however, there…

  13. Africans Away from Home.

    ERIC Educational Resources Information Center

    Clarke, John Henrik

    Africans who were brought across the Atlantic as slaves never fully adjusted to slavery or accepted its inevitability. Resistance began on board the slave ships, where many jumped overboard or committed suicide. African slaves in South America led the first revolts against tyranny in the New World. The first slave revolt in the Caribbean occurred…

  14. Educating African American Males

    ERIC Educational Resources Information Center

    Bell, Edward E.

    2010-01-01

    Background: Schools across America spend money, invest in programs, and sponsor workshops, offer teacher incentives, raise accountability standards, and even evoke the name of Obama in efforts to raise the academic achievement of African American males. Incarceration and college retention rates point to a dismal plight for many African American…

  15. 16 Extraordinary African Americans.

    ERIC Educational Resources Information Center

    Lobb, Nancy

    This collection for children tells the stories of 16 African Americans who helped make America what it is today. African Americans can take pride in the heritage of these contributors to society. Biographies are given for the following: (1) Sojourner Truth, preacher and abolitionist; (2) Frederick Douglass, abolitionist; (3) Harriet Tubman, leader…

  16. Keeping African Masks Real

    ERIC Educational Resources Information Center

    Waddington, Susan

    2012-01-01

    Art is a good place to learn about our multicultural planet, and African masks are prized throughout the world as powerfully expressive artistic images. Unfortunately, multicultural education, especially for young children, can perpetuate stereotypes. Masks taken out of context lose their meaning and the term "African masks" suggests that there is…

  17. Plate-induced Miocene extension in southern California

    SciTech Connect

    Stuart, W.D. Univ. of California, Santa Barbara, CA )

    1992-01-01

    Miocene crustal extension in southern California can be explained by the interaction of tectonic plates in relative motion. The Pacific, Juan de Fuca, and Farallon (Guadalupe) plates are represented by flat elastic plates surrounded by an infinite elastic plate, the eastern part of which represents the North America plate. Forcing is by assigned subduction pull, and tractions at all plate boundaries satisfy a viscous constitutive law. Plate bottoms are stress-free. In the first part of the solution plate velocities and boundary tractions are found from static equilibrium. Then principal horizontal stresses and strains in plate interiors caused by tractions and subduction pull are found by a boundary element procedure. Using plate boundary geometry from Stock and Hodges for early- and mid-Miocene times, it is found that the portion of the North America plate margin between the Mendocino and Rivera triple junctions has maximum extensional strain directed westward. This result is generally consistent with directions associated with metamorphic core complex formation in southern California. The model is also consistent with extensional strain and rotation sense of crustal blocks in the vicinity of Los Angeles, as inferred by Luyendyk and others from paleomagnetic data. In the model the greatest extensional strain of the North America plate occurs near the Pacific-North America transform, in the area above the absent Farallon slab. Extension direction varies from northwest to southwest according to plate geometry, subduction pull (Juan de Fuca and Guadalupe), and plate boundary tractions.

  18. Range and Frequency of Africanized Honey Bees in California (USA)

    PubMed Central

    Kono, Yoshiaki; Kohn, Joshua R.

    2015-01-01

    Africanized honey bees entered California in 1994 but few accounts of their northward expansion or their frequency relative to European honey bees have been published. We used mitochondrial markers and morphometric analyses to determine the prevalence of Africanized honeybees in San Diego County and their current northward progress in California west of the Sierra Nevada crest. The northernmost African mitotypes detected were approximately 40 km south of Sacramento in California’s central valley. In San Diego County, 65% of foraging honey bee workers carry African mitochondria and the estimated percentage of Africanized workers using morphological measurements is similar (61%). There was no correlation between mitotype and morphology in San Diego County suggesting Africanized bees result from bidirectional hybridization. Seventy percent of feral hives, but only 13% of managed hives, sampled in San Diego County carried the African mitotype indicating that a large fraction of foraging workers in both urban and rural San Diego County are feral. We also found a single nucleotide polymorphism at the DNA barcode locus COI that distinguishes European and African mitotypes. The utility of this marker was confirmed using 401 georeferenced honey bee sequences from the worldwide Barcode of Life Database. Future censuses can determine whether the current range of the Africanized form is stable, patterns of introgression at nuclear loci, and the environmental factors that may limit the northern range of the Africanized honey bee. PMID:26361047

  19. Range and Frequency of Africanized Honey Bees in California (USA).

    PubMed

    Kono, Yoshiaki; Kohn, Joshua R

    2015-01-01

    Africanized honey bees entered California in 1994 but few accounts of their northward expansion or their frequency relative to European honey bees have been published. We used mitochondrial markers and morphometric analyses to determine the prevalence of Africanized honeybees in San Diego County and their current northward progress in California west of the Sierra Nevada crest. The northernmost African mitotypes detected were approximately 40 km south of Sacramento in California's central valley. In San Diego County, 65% of foraging honey bee workers carry African mitochondria and the estimated percentage of Africanized workers using morphological measurements is similar (61%). There was no correlation between mitotype and morphology in San Diego County suggesting Africanized bees result from bidirectional hybridization. Seventy percent of feral hives, but only 13% of managed hives, sampled in San Diego County carried the African mitotype indicating that a large fraction of foraging workers in both urban and rural San Diego County are feral. We also found a single nucleotide polymorphism at the DNA barcode locus COI that distinguishes European and African mitotypes. The utility of this marker was confirmed using 401 georeferenced honey bee sequences from the worldwide Barcode of Life Database. Future censuses can determine whether the current range of the Africanized form is stable, patterns of introgression at nuclear loci, and the environmental factors that may limit the northern range of the Africanized honey bee.

  20. Tectonic Plate Parameters Estimated in the International Terrestrial Reference Frame ITRF2008 Based on SLR Stations

    NASA Astrophysics Data System (ADS)

    Kraszewska, Katarzyna; Jagoda, Marcin; Rutkowska, Miłosława

    2016-10-01

    This paper concerns an analysis of the accuracy of estimated parameters Ω (Φ, Λ, ω) which define the tectonic plate motions. The study is based on the velocities of station positions published by ITRF2008 for Satellite Laser Ranging (SLR) technique. The Eurasian, African, North American and Australian plates were used in the analysis. Influence of the number and location of stations on the plate surface on estimation accuracy of the tectonic plate motion parameters was discussed. The results were compared with the APKIM 2005 IGN model. In general, a remarkable concurrence agreement between our solutions and the APKIM 2005 model was found.